Organometallic compound, organic light-emitting device including the same, and diagnostic composition including the organometallic compound

ABSTRACT

An organometallic compound represented by Formula 1: 
     
       
         
         
             
             
         
       
         
         
           
             wherein, in Formula 1, groups and variables are the same as described in the specification.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to Korean Patent Application No. 10-2017-0094963, filed on Jul. 26, 2017, in the Korean Intellectual Property Office, and all the benefits accruing therefrom under 35 U.S.C. § 119, the content of which is incorporated herein in its entirety by reference.

BACKGROUND 1. Field

One or more embodiments relate to an organometallic compound, an organic light-emitting device including the organometallic compound, and a diagnostic composition including the organometallic compound.

2. Description of the Related Art

Organic light-emitting devices (OLEDs) are self-emission devices, which have superior characteristics in terms of a viewing angle, a response time, luminance, a driving voltage, and a response speed, and which produce full-color images.

In an example, an organic light-emitting device includes an anode, a cathode, and an organic layer disposed between the anode and the cathode, wherein the organic layer includes an emission layer. A hole transport region may be disposed between the anode and the emission layer, and an electron transport region may be disposed between the emission layer and the cathode. Holes provided from the anode may move toward the emission layer through the hole transport region, and electrons provided from the cathode may move toward the emission layer through the electron transport region. The holes and the electrons recombine in the emission layer to produce excitons. These excitons transit from an excited state to a ground state, thereby generating light.

Meanwhile, luminescent compounds may be used to monitor, sense, or detect a variety of biological materials including cells and proteins. An example of such luminescent compounds is a phosphorescent luminescent compound.

Various types of organic light emitting devices are known. However, there still remains a need in OLEDs having low driving voltage, high efficiency, high brightness, and long lifespan.

SUMMARY

Aspects of the present disclosure provide an organometallic compound, an organic light-emitting device including the organometallic compound, and a diagnostic composition including the organometallic compound.

Additional aspects will be set forth in part in the description which follows and, in part, will be apparent from the description, or may be learned by practice of the presented embodiments.

According to one or more embodiments, an organometallic compound represented by Formula 1 is provided.

In Formula 1,

-   -   M may be beryllium (Be), magnesium (Mg), aluminum (Al), calcium         (Ca), titanium (Ti), manganese (Mn), cobalt (Co), copper (Cu),         zinc (Zn), gallium (Ga), germanium (Ge), zirconium (Zr),         rhutenium (Ru), rhodium (Rh), palladium (Pd), silver (Ag),         rhenium (Re), platinum (Pt), or gold (Au),     -   X₁ may be a chemical bond, O, S, N(R′), P(R′), B(R′), C(R′)(R″),         Si(R′)(R″), or N(R′)(R″), and when X₁ is a chemical bond, Y₁ is         directly bonded with M,     -   a bond between X₁ and M may be a covalent bond,     -   X₂ to X₄ may each independently be N or C,     -   one bond selected from a bond between X₂ and M, a bond between         X₃ and M, and a bond between X₄ and M is a covalent bond, and         the remaining two bonds are coordinate bonds,     -   Y₁ and Y₃ to Y₅ may each independently be C or N,     -   regarding a pair of X₂ and Y₃, a pair of X₂ and Y₄, a pair of Y₄         and Y₅, a pair of X₅₁ and Y₃, and a pair of X₅₁ and Y₅,         components constituting each pair may be connected to each other         via a chemical bond,     -   CY₁ to CY₅ may each independently be selected from a C₅-C₃₀         carbocyclic group and a C₁-C₃₀ heterocyclic group,     -   a cyclometalated ring formed by CY₅, CY₂, CY₃, and M may be a         6-membered ring,     -   X₅₁ may be selected from O, S, N-[(L₇)_(b7)-(R₇)_(c7)],         C(R₇)(R₈), Si(R₇)(R₈), Ge(R₇)(R₈), C(═O), N, C(R₇), Si(R₇), and         Ge(R₇),     -   R₇ and R₈ may be optionally bonded to each other via a first         linking group to form a substituted or unsubstituted C₅-C₃₀         carbocyclic group or a substituted or unsubstituted C₁-C₃₀         heterocyclic group,     -   L₁ to L₄ and L₇ may each independently be selected from a single         bond, a substituted or unsubstituted C₅-C₃₀ carbocyclic group,         and a substituted or unsubstituted C₁-C₃₀ heterocyclic group,     -   b1 to b4 and b7 may each independently be an integer from 1 to         5,     -   R₁ to R₄, R₇, R₈, R′, and R″ may each independently selected         from hydrogen, deuterium, —F, —Cl, —Br, —I, —SF₅, a hydroxyl         group, a cyano group, a nitro group, an amidino group, a         hydrazine group, a hydrazone group, a carboxylic acid group or a         salt thereof, a sulfonic acid group or a salt thereof, a         phosphoric acid group or a salt thereof, a substituted or         unsubstituted C₁-C₆₀ alkyl group, a substituted or unsubstituted         C₂-C₆₀ alkenyl group, a substituted or unsubstituted C₂-C₆₀         alkynyl group, a substituted or unsubstituted C₁-C₆₀ alkoxy         group, a substituted or unsubstituted C₃-C₁₀ cycloalkyl group, a         substituted or unsubstituted C₁-C₁₀ heterocycloalkyl group, a         substituted or unsubstituted C₃-C₁₀ cycloalkenyl group, a         substituted or unsubstituted C₁-C₁₀ heterocycloalkenyl group, a         substituted or unsubstituted C₆-C₆₀ aryl group, a substituted or         unsubstituted C₆-C₆₀ aryloxy group, a substituted or         unsubstituted C₆-C₆₀ arylthio group, a substituted or         unsubstituted C₁-C₆₀ heteroaryl group, a substituted or         unsubstituted monovalent non-aromatic condensed polycyclic         group, a substituted or unsubstituted monovalent non-aromatic         condensed heteropolycyclic group, —N(Q₁)(Q₂), —Si(Q₃)(Q₄)(Q₅),         —B(Q₆)(Q₇), and —P(═O)(Q₈)(Q₉),     -   c1 to c4 and c7 may each independently be an integer from 1 to         5,     -   Z₁ to Z₄ may each independently be a cyano group (CN)-containing         group,     -   a1 to a4 and n1, n2, n3, and n4 may each independently be an         integer from 0 to 20,     -   two of a plurality of neighboring groups R₁ may optionally be         linked to form a substituted or unsubstituted C₅-C₃₀ carbocyclic         group or a substituted or unsubstituted C₁-C₃₀ heterocyclic         group,     -   two of a plurality of neighboring groups R₂ may optionally be         linked to form a substituted or unsubstituted C₅-C₃₀ carbocyclic         group or a substituted or unsubstituted C₁-C₃₀ heterocyclic         group,     -   two of a plurality of neighboring groups R₃ may optionally be         linked to form a substituted or unsubstituted C₅-C₃₀ carbocyclic         group or a substituted or unsubstituted C₁-C₃₀ heterocyclic         group,     -   two of a plurality of neighboring groups R₄ may optionally be         linked to form a substituted or unsubstituted C₅-C₃₀ carbocyclic         group or a substituted or unsubstituted C₁-C₃₀ heterocyclic         group,     -   two or more neighboring substituents selected from groups R₁ to         R₄, R₇, and R₈ may optionally be linked to form a substituted or         unsubstituted C₅-C₃₀ carbocyclic group or a substituted or         unsubstituted C₁-C₃₀ heterocyclic group,     -   i) when X₅₁ is O, S, C(═O), or N, the sum of n1, n2, n3, and n4         may be 1 or more,     -   ii) when X₅₁ is N[(L₇)_(b7)-(R₇)_(c7)], C(R₇), Si(R₇), or         Ge(R₇), R₇ may be a cyano group-containing group or the sum of         n1, n2, n3, and n4 may be 1 or more, iii) when X₅₁ is C(R₇)(R₈),         Si(R₇)(R₈), or Ge(R₇)(R₈), at least one selected from R₇ and R₈         may be a cyano group-containing group or the sum of n1, n2, n3,         and n4 may be 1 or more,     -   at least one of substituents of the substituted C₅-C₃₀         carbocyclic group, substituted C₁-C₃₀ heterocyclic group,         substituted C₁-C₆₀ alkyl group, substituted C₂-C₆₀ alkenyl         group, substituted C₂-C₆₀ alkynyl group, substituted C₁-C₆₀         alkoxy group, substituted C₃-C₁₀ cycloalkyl group, substituted         C₁-C₁₀ heterocycloalkyl group, substituted C₃-C₁₀ cycloalkenyl         group, substituted C₁-C₁₀ heterocycloalkenyl group, substituted         C₆-C₆₀ aryl group, substituted C₆-C₆₀ aryloxy group, substituted         C₆-C₆₀ arylthio group, substituted C₁-C₆₀ heteroaryl group,         substituted monovalent non-aromatic condensed polycyclic group,         and substituted monovalent non-aromatic condensed         heteropolycyclic group may be selected from:     -   deuterium, —F, —Cl, —Br, —I, —CD₃, —CD₂H, —CDH₂, —CF₃, —CF₂H,         —CFH₂, a hydroxyl group, a cyano group, a nitro group, an         amidino group, a hydrazine group, a hydrazone group, a         carboxylic acid group or a salt thereof, a sulfonic acid group         or a salt thereof, a phosphoric acid group or a salt thereof, a         C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl         group, and a C₁-C₆₀ alkoxy group;     -   a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl         group, and a C₁-C₆₀ alkoxy group, each substituted with at least         one selected from deuterium, —F, —Cl, —Br, —I, —CD₃, —CD₂H,         —CDH₂, —CF₃, —CF₂H, —CFH₂, a hydroxyl group, a cyano group, a         nitro group, an amidino group, a hydrazine group, a hydrazone         group, a carboxylic acid group or a salt thereof, a sulfonic         acid group or a salt thereof, a phosphoric acid group or a salt         thereof, a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl         group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl         group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀         arylthio group, a C₁-C₆₀ heteroaryl group, a monovalent         non-aromatic condensed polycyclic group, a monovalent         non-aromatic condensed heteropolycyclic group, —N(Q₁₁)(Q₁₂),         —Si(Q₁₃)(Q₁₄)(Q₁₅), —B(Q₁₆)(Q₁₇), and —P(═O)(Q₁₈)(Q₁₉);     -   a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a         C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a         C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio         group, a C₁-C₆₀ heteroaryl group, a monovalent non-aromatic         condensed polycyclic group, and a monovalent non-aromatic         condensed heteropolycyclic group;     -   a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a         C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a         C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio         group, a C₁-C₆₀ heteroaryl group, a monovalent non-aromatic         condensed polycyclic group, and a monovalent non-aromatic         condensed heteropolycyclic group, each substituted with at least         one selected from deuterium, —F, —Cl, —Br, —I, —CD₃, —CD₂H,         —CDH₂, —CF₃, —CF₂H, —CFH₂, a hydroxyl group, a cyano group, a         nitro group, an amidino group, a hydrazine group, a hydrazone         group, a carboxylic acid group or a salt thereof, a sulfonic         acid group or a salt thereof, a phosphoric acid group or a salt         thereof, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀         alkynyl group, a C₁-C₆₀ alkoxy group, a C₃-C₁₀ cycloalkyl group,         a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a         C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀         aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl         group, a monovalent non-aromatic condensed polycyclic group, a         monovalent non-aromatic condensed heteropolycyclic group,         —N(Q₂₁)(Q₂₂), —Si(Q₂₃)(Q₂₄)(Q₂₅), —B(Q₂₆)(Q₂₇), and         —P(═O)(Q₂₈)(Q₂₉); and     -   —N(Q₃₁)(Q₃₂), —Si(Q₃₃)(Q₃₄)(Q₃₅), —B(Q₃₆)(Q₃₇) and         —P(═O)(Q₃₈)(Q₃₉),     -   wherein Q₁ to Q₉, Q₁₁ to Q₁₉, Q₂₁ to Q₂₉ and Q₃₁ to Q₃₉ may each         independently be selected from hydrogen, deuterium, —F, —Cl,         —Br, —I, a hydroxyl group, a cyano group, a nitro group, an         amidino group, a hydrazine group, a hydrazone group, a         carboxylic acid group or a salt thereof, a sulfonic acid group         or a salt thereof, a phosphoric acid group or a salt thereof, a         C₁-C₆₀ alkyl group, a C₁-C₆₀ alkyl group substituted with at         least one selected from deuterium, a C₁-C₆₀ alkyl group, and a         C₆-C₆₀ aryl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl         group, a C₁-C₆₀ alkoxy group, a C₃-C₁₀ cycloalkyl group, a         C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a         C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀         aryl group substituted with at least one selected from         deuterium, a C₁-C₆₀ alkyl group, and a C₆-C₆₀ aryl group, a         C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀         heteroaryl group, a monovalent non-aromatic condensed polycyclic         group, and a monovalent non-aromatic condensed heteropolycyclic         group.

Another aspect of the present disclosure provides an organic light-emitting device including:

-   -   a first electrode,     -   a second electrode, and     -   an organic layer disposed between the first electrode and the         second electrode,     -   wherein the organic layer includes an emission layer and at         least one organometallic compound.

The organometallic compound of the organic layer may act as a dopant.

Another aspect of the present disclosure provides a diagnostic composition including at least one organometallic compound represented by Formula 1.

BRIEF DESCRIPTION OF THE DRAWING

These and/or other aspects will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the FIGURE which is a schematic view of an organic light-emitting device according to an embodiment.

DETAILED DESCRIPTION

Reference will now be made in detail to embodiments, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout. In this regard, the present embodiments may have different forms and should not be construed as being limited to the descriptions set forth herein. Accordingly, the embodiments are merely described below, by referring to the figures, to explain aspects. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. Expressions such as “at least one of,” when preceding a list of elements, modify the entire list of elements and do not modify the individual elements of the list.

It will be understood that when an element is referred to as being “on” another element, it can be directly in contact with the other element or intervening elements may be present therebetween. In contrast, when an element is referred to as being “directly on” another element, there are no intervening elements present.

It will be understood that, although the terms first, second, third etc. may be used herein to describe various elements, components, regions, layers, and/or sections, these elements, components, regions, layers, and/or sections should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer, or section from another element, component, region, layer, or section. Thus, a first element, component, region, layer, or section discussed below could be termed a second element, component, region, layer, or section without departing from the teachings of the present embodiments.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting. As used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise.

The term “or” means “and/or.” It will be further understood that the terms “comprises” and/or “comprising,” or “includes” and/or “including” when used in this specification, specify the presence of stated features, regions, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, regions, integers, steps, operations, elements, components, and/or groups thereof.

Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this general inventive concept belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and the present disclosure, and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

Exemplary embodiments are described herein with reference to cross section illustrations that are schematic illustrations of idealized embodiments. As such, variations from the shapes of the illustrations as a result, for example, of manufacturing techniques and/or tolerances, are to be expected. Thus, embodiments described herein should not be construed as limited to the particular shapes of regions as illustrated herein but are to include deviations in shapes that result, for example, from manufacturing. For example, a region illustrated or described as flat may, typically, have rough and/or nonlinear features. Moreover, sharp angles that are illustrated may be rounded. Thus, the regions illustrated in the figures are schematic in nature and their shapes are not intended to illustrate the precise shape of a region and are not intended to limit the scope of the present claims.

“About” or “approximately” as used herein is inclusive of the stated value and means within an acceptable range of deviation for the particular value as determined by one of ordinary skill in the art, considering the measurement in question and the error associated with measurement of the particular quantity (i.e., the limitations of the measurement system). For example, “about” can mean within one or more standard deviations, or within ±30%, 20%, 10%, 5% of the stated value.

In an embodiment, an organometallic compound is provided. The organometallic compound according to an embodiment is represented by Formula 1 below:

M in Formula 1 may be beryllium (Be), magnesium (Mg), aluminum (Al), calcium (Ca), titanium (Ti), manganese (Mn), cobalt (Co), copper (Cu), zinc (Zn), gallium (Ga), germanium (Ge), zirconium (Zr), rhutenium (Ru), rhodium (Rh), palladium (Pd), silver (Ag), rhenium (Re), platinum (Pt), or gold (Au).

For example, M in Formula 1 may be platinum, but embodiments of the present disclosure are not limited thereto.

The organometallic compound represented by Formula 1 may not consist of an ion pair of a cation and an anion, that is, may be neutral.

X₁ in Formula 1 may be a chemical bond (for example, a single bond or a covalent bond), O, S, N(R′), P(R′), B(R′), C(R′)(R″), Si(R′)(R″), or N(R′)(R″), and a bond between X₁ and M may be a covalent bond. When X₁ is a chemical bond, Y₁ may be directly bonded with M.

For example, X₁ in Formula 1 may be chemical bond or O, but embodiments of the present disclosure are not limited thereto.

In Formula 1, X₂ to X₄ may each independently be N or C, and one bond selected from a bond between X₂ and M, a bond between X₃ and M, and a bond between X₄ and M may be a covalent bond, and the remaining two bonds may each be a coordinate bond.

For example, in Formula 1,

-   -   i) X₂ and X₄ may each be N, X₃ may be C, a bond between X₂ and M         and a bond between X₄ and M may each be a coordinate bond, and a         bond between X₃ and M may be a covalent bond,     -   ii) X₃ and X₄ may each be N, X₂ may be N, a bond between X₃ and         M and a bond between X₄ and M may each be a coordinate bond, and         a bond between X₂ and M may be a covalent bond,     -   iii) X₂ and X₃ may each be N, X₄ may be N, a bond between X₂ and         M may be a covalent bond, and a bond between X₃ and M and a bond         between X₄ and M may each be coordinate bond, or     -   iv) X₂ and X₃ may each be N, X₄ may be C, a bond between X₂ and         M and a bond between X₃ and M may each be a coordinate bond, and         a bond between X₄ and M may be a covalent bond, but embodiments         of the present disclosure are not limited thereto.

Y₁ and Y₃ to Y₅ in Formula 1 may each independently be C or N.

A pair of X₂ and Y₃, a pair of X₂ and Y₄, a pair of Y₄ and Y₅, a pair of X₅₁ and Y₃, and a pair of X₅₁ and Y₅ in Formula 1 may each be bonded via a chemical bond (for example, a single bond, a double bond, a bond constituting a carbene ligand, or the like) to form a part of CY₁ to CY₅.

CY₁ to CY₅ in Formula 1 may each independently be selected from a C₅-C₃₀ carbocyclic group and a C₁-C₃₀ heterocyclic group.

In one or more embodiments, in Formula 1,

-   -   CY₁, CY₂, and CY₄ may each independently be a 6-membered ring         group,     -   CY₃ may be selected from a 6-membered ring group, a fluorene         group, a carbazole group, a dibenzofuran group, a         dibenzothiophene group, a dibenzosilole group, an azafluorene         group, an azacarbazole group, an azadibenzofuran group, an         azadibenzothiophene group, and an azadibenzosilole group,     -   CY₅ may be a 5-membered ring.

In one or more embodiments, CY₁ to CY₄ in Formula 1 may each independently be selected from a benzene group, a naphthalene group, an anthracene group, a phenanthrene group, a triphenylene group, a pyrene group, a chrysene group, a cyclopentadiene group, a 1,2,3,4-tetrahydronaphthalene group, a furan group, a thiophene group, a silole group, an indene group, a fluorene group, an indole group, a carbazole group, a benzofuran group, a dibenzofuran group, a benzothiophene group, a dibenzothiophene group, a benzosilole group, a dibenzosilole group, an azafluorene group, an azacarbazole group, an azadibenzofuran group, an azadibenzothiophene group, an azadibenzosilole group, a pyridine group, a pyrimidine group, a pyrazine group, a pyridazine group, a triazine group, a quinoline group, an isoquinoline group, a quinoxaline group, a quinazoline group, phenanthroline group, a pyrrole group, a pyrazole group, an imidazole group, a triazole group, an oxazole group, an iso-oxazole group, a thiazole group, an isothiazole group, an oxadiazole group, a thiadiazole group, a benzopyrazole group, a benzimidazole group, a benzoxazole group, a benzothiazole group, a benzooxadiazole group, a benzothiadiazole group, a 5,6,7,8-tetrahydroisoquinoline group, and a 5,6,7,8-tetrahydroquinoline group, but embodiments of the present disclosure are not limited thereto.

In one or more embodiments, CY₁ to CY₄ in Formula 1 may each independently be selected from a) 6-membered ring, b) a condensed ring in which two or more 6-membered rings are condensed with each other, or c) a condensed ring in which one or more 6-membered ring is condensed with one or more 5-membered ring,

the 6-membered ring may be selected from a cyclohexane group, a cyclohexene group, an adamantane group, a norbornane group, a norbornene group, a benzene group, a pyridine group, a pyrimidine group, a pyrazine group, a pyridazine group, and a triazine group, and

the 5-membered ring may be selected from a cyclopentane group, a cyclopentene group, a cyclopentadiene group, a furan group, a thiophene group, a silole group, a pyrrole group, a pyrazole group, an imidazole group, a triazole group, an oxazole group, an isoxazole group, a thiazole group, an isothiazole group, an oxadiazole group and thiadiazole group.

A cyclometalated ring formed by CY₅, CY₂, CY₃, and M in Formula 1 is a 6-membered ring.

X₅₁ in Formula 1 may be selected from O, S, N-[(L₇)_(b7)-(R₇)_(c7)], C(R₇)(R₈), Si(R₇)(R₈), Ge(R₇)(R₈), C(═O), N, C(R₇), Si(R₇), and Ge(R₇), and R₇ and R₈ may optionally be linked via a first linking group to form a substituted or unsubstituted C₅-C₃₀ carbocyclic group or a substituted or unsubstituted C₁-C₃₀ heterocyclic group (for example, a 5-membered to 7-membered cyclic group having the carbon number of 5 or 6; or a 5-membered to 7-membered cyclic group of which the carbon number is 5 or 6 and which is substituted with at least one selected from deuterium, a cyano group, —F, a C₁-C₁₀ alkyl group, and a C₆-C₁₄ aryl group). L₇, b7, R₇, R₈, and c7 will be described in detail.

The first linking group may be selected from a single bond, *—O—*′, *—S—*′, *—C(R₅)(R₆)—*′, *—C(R₅)=*′, *═C(R₆)—*′, *—C(R₅)═C(R₆)—*′, *—C(═O)—*′, *—C(═S)—*′, *—C≡C—*′, *—N(R₅)—*′, *—Si(R₅)(R₆)—*′, and *—P(R₅)(R₆)—*′, R₅ and R₆ may be the same as described in connection with R₁, and * and *′ each indicate a binding site to a neighboring atom.

In one or more embodiments, in Formula 1,

-   -   i) Y₃ to Y₅ may each be C, a bond between X₅₁ and Y₃ and a bond         between X₅₁ and Y₅ may each be a single bond, and X₅₁ may be O,         S, N-[(L₇)_(b7)-(R₇)_(c7)], C(R₇)(R₈), Si(R₇)(R₈), Ge(R₇)(R₈),         or C(═O),     -   ii) Y₃ and Y₄ may each be C, Y₅ may be N, a bond between X₅₁ and         Y₃ may be a double bond, a bond between X₅₁ and Y₅ may be a         single bond, and X₅₁ may be N, C(R₇), Si(R₇), or Ge(R₇),     -   iii) Y₃ and Y₅ may each be C, Y₄ may be N, a bond between X₅₁         and Y₃ may be a single bond, a bond between X₅₁ and Y₅ may be a         double bond, and X₅₁ may be N, C(R₇), Si(R₇), or Ge(R₇),     -   iv) Y₃ may be N, Y₄ and Y₅ may each be C, a bond between X₅₁ and         Y₃ may be a single bond, a bond between X₅₁ and Y₅ may be a         double bond, and X₅₁ may be N, C(R₇), Si(R₇), or Ge(R₇), or     -   v) Y₃ to Y₅ may each be C, a bond between X₅₁ and Y₃ may be a         double bond, a bond between X₅₁ and Y₅ may be a single bond, and         X₅₁ may be N, C(R₇), Si(R₇), or Ge(R₇).

L₁ to L₄ and L₇ in Formula 1 may each independently be selected from a single bond, a substituted or unsubstituted C₅-C₃₀ carbocyclic group, and a substituted or unsubstituted C₁-C₃₀ heterocyclic group.

For example, L₁ to L₄ and L₇ in Formula 1 may each independently be selected from:

a single bond, a benzene group, a naphthalene group, an anthracene group, a phenanthrene group, a triphenylene group, a pyrene group, a chrysene group, a cyclopentadiene group, a furan group, a thiophene group, a silole group, an indene group, a fluorene group, an indole group, a carbazole group, a benzofuran group, a dibenzofuran group, a benzothiophene group, a dibenzothiophene group, a benzosilole group, a dibenzosilole group, an azafluorene group, an azacarbazole group, an azadibenzofuran group, an azadibenzothiophene group, an azadibenzosilole group, a pyridine group, a pyrimidine group, a pyrazine group, a pyridazine group, a triazine group, a quinoline group, an isoquinoline group, a quinoxaline group, a quinazoline group, phenanthroline group, a pyrrole group, a pyrazole group, an imidazole group, a triazole group, an oxazole group, an iso-oxazole group, a thiazole group, an isothiazole group, an oxadiazole group, a thiadiazole group, a benzopyrazole group, a benzimidazole group, a benzoxazole group, a benzothiazole group, a benzooxadiazole group, and a benzothiadiazole group; and

a benzene group, a naphthalene group, an anthracene group, a phenanthrene group, a triphenylene group, a pyrene group, a chrysene group, a cyclopentadiene group, a furan group, a thiophene group, a silole group, an indene group, a fluorene group, an indole group, a carbazole group, a benzofuran group, a dibenzofuran group, a benzothiophene group, a dibenzothiophene group, a benzosilole group, a dibenzosilole group, an azafluorene group, an azacarbazole group, an azadibenzofuran group, an azadibenzothiophene group, an azadibenzosilole group, a pyridine group, a pyrimidine group, a pyrazine group, a pyridazine group, a triazine group, a quinoline group, an isoquinoline group, a quinoxaline group, a quinazoline group, phenanthroline group, a pyrrole group, a pyrazole group, an imidazole group, a triazole group, an oxazole group, an iso-oxazole group, a thiazole group, an isothiazole group, an oxadiazole group, a thiadiazole group, a benzopyrazole group, a benzimidazole group, a benzoxazole group, a benzothiazole group, a benzooxadiazole group, and a benzothiadiazole group, each substituted with at least one selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, a phenyl group, a naphthyl group, a pyridinyl group, a pyrimidinyl group, a triazinyl group, a fluorenyl group, a dimethylfluorenyl group, a diphenylfluorenyl group, a carbazolyl group, a phenylcarbazolyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a dibenzosilolyl group, a dimethyldibenzosilolyl group, a diphenyldibenzosilolyl group, —N(Q₃₁)(Q₃₂), —Si(Q₃₃)(Q₃₄)(Q₃₅), —B(Q₃₆)(Q₃₇), and —P(═O)(Q₃₈)(Q₃₉);

-   -   Q₃₁ to Q₃₉ may each independently be selected from:     -   —CH₃, —CD₃, —CD₂H, —CDH₂, —CH₂CH₃, —CH₂CD₃, —CH₂CD₂H, —CH₂CDH₂,         —CHDCH₃, —CHDCD₂H, —CHDCDH₂, —CHDCD₃, —CD₂CD₃, —CD₂CD₂H, and         —CD₂CDH₂;     -   an n-propyl group, an iso-propyl group, an n-butyl group, an         iso-butyl group, a sec-butyl group, a tert-butyl group, an         n-pentyl group, an iso-pentyl group, a sec-pentyl group, a         tert-pentyl group, a phenyl group, and a naphthyl group; and     -   an n-propyl group, an iso-propyl group, an n-butyl group, an         iso-butyl group, a sec-butyl group, a tert-butyl group, an         n-pentyl group, an iso-pentyl group, a sec-pentyl group, a         tert-pentyl group, a phenyl group, and a naphthyl group, each         substituted with at least one selected from deuterium, a C₁-C₁₀         alkyl group, and a phenyl group,     -   but embodiments of the present disclosure are not limited         thereto.

b1 to b4 and b7 in Formula 1 indicate numbers of L₁ to L₄ and L₇, respectively, and may each independently an integer from 1 to 5. When b1 is 2 or more, two or more groups L₁ may be identical to or different from each other. b2 to b4 and b7 may each be the same as described in connection with b1.

In an embodiment, b1 to b4 and b7 in Formula 1 may each be 1 or 2, but embodiments of the present disclosure are not limited thereto.

R₁ to R₄, R₇, R₈, R′ and R″ in Formula 1 may each independently be selected from hydrogen, deuterium, —F, —Cl, —Br, —I, —SF₅, a hydroxyl group, a cyano group, a nitro group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a substituted or unsubstituted C₁-C₆₀ alkyl group, a substituted or unsubstituted C₂-C₆₀ alkenyl group, a substituted or unsubstituted C₂-C₆₀ alkynyl group, a substituted or unsubstituted C₁-C₆₀ alkoxy group, a substituted or unsubstituted C₃-C₁₀ cycloalkyl group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkyl group, a substituted or unsubstituted C₃-C₁₀ cycloalkenyl group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkenyl group, a substituted or unsubstituted C₆-C₆₀ aryl group, a substituted or unsubstituted C₆-C₆₀ aryloxy group, a substituted or unsubstituted C₆-C₆₀ arylthio group, a substituted or unsubstituted C₁-C₆₀ heteroaryl group, a substituted or unsubstituted monovalent non-aromatic condensed polycyclic group, a substituted or unsubstituted monovalent non-aromatic condensed heteropolycyclic group, —N(Q₁)(Q₂), —Si(Q₃)(Q₄)(Q₅), —B(Q₆)(Q₇), and —P(═O)(Q₈)(Q₉).

For example, R₁ to R₄, R₇, R₈, R′, and R″ may each independently be selected from:

-   -   hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano         group, a nitro group, an amino group, an amidino group, a         hydrazine group, a hydrazone group, a carboxylic acid group or a         salt thereof, a sulfonic acid group or a salt thereof, a         phosphoric acid group or a salt thereof, —SF₅, C₁-C₂₀ alkyl         group, and a C₁-C₂₀ alkoxy group;     -   a C₁-C₂₀ alkyl group and a C₁-C₂₀ alkoxy group, each substituted         with at least one selected from deuterium, —F, —Cl, —Br, —I,         —CD₃, —CD₂H, —CDH₂, —CF₃, —CF₂H, —CFH₂, a hydroxyl group, a         cyano group, a nitro group, an amino group, an amidino group, a         hydrazine group, a hydrazone group, a carboxylic acid group or a         salt thereof, a sulfonic acid group or a salt thereof, a         phosphoric acid group or a salt thereof, a C₁-C₁₀ alkyl group, a         cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a         cyclooctyl group, an adamantanyl group, a norbornanyl group, a         norbornenyl group, a cyclopentenyl group, a cyclohexenyl group,         a cycloheptenyl group, a phenyl group, a naphthyl group, a         pyridinyl group, and a pyrimidinyl group;     -   a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a         cyclooctyl group, an adamantanyl group, a norbornanyl group, a         norbornenyl group, a cyclopentenyl group, a cyclohexenyl group,         a cycloheptenyl group, a phenyl group, a naphthyl group, a         fluorenyl group, a phenanthrenyl group, an anthracenyl group, a         fluoranthenyl group, a triphenylenyl group, a pyrenyl group, a         chrysenyl group, a pyrrolyl group, a thiophenyl group, a furanyl         group, an imidazolyl group, a pyrazolyl group, a thiazolyl         group, an isothiazolyl group, an oxazolyl group, an isoxazolyl         group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl         group, a pyridazinyl group, an isoindolyl group, an indolyl         group, an indazolyl group, a purinyl group, a quinolinyl group,         an isoquinolinyl group, a benzoquinolinyl group, a quinoxalinyl         group, a quinazolinyl group, a cinnolinyl group, a carbazolyl         group, a phenanthrolinyl group, a benzimidazolyl group, a         benzofuranyl group, a benzothiophenyl group, an         isobenzothiazolyl group, a benzoxazolyl group, an         isobenzoxazolyl group, a triazolyl group, a tetrazolyl group, an         oxadiazolyl group, a triazinyl group, a dibenzofuranyl group, a         dibenzothiophenyl group, a dibenzosilolyl group, a         benzocarbazolyl group, a dibenzocarbazolyl group, an         imidazopyridinyl group, and an imidazopyrimidinyl group;     -   a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a         cyclooctyl group, an adamantanyl group, a norbornanyl group, a         norbornenyl group, a cyclopentenyl group, a cyclohexenyl group,         a cycloheptenyl group, a phenyl group, a naphthyl group, a         fluorenyl group, a phenanthrenyl group, an anthracenyl group, a         fluoranthenyl group, a triphenylenyl group, a pyrenyl group, a         chrysenyl group, a pyrrolyl group, a thiophenyl group, a furanyl         group, an imidazolyl group, a pyrazolyl group, a thiazolyl         group, an isothiazolyl group, an oxazolyl group, an isoxazolyl         group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl         group, a pyridazinyl group, an isoindolyl group, an indolyl         group, an indazolyl group, a purinyl group, a quinolinyl group,         an isoquinolinyl group, a benzoquinolinyl group, a quinoxalinyl         group, a quinazolinyl group, a cinnolinyl group, a carbazolyl         group, a phenanthrolinyl group, a benzimidazolyl group, a         benzofuranyl group, a benzothiophenyl group, an         isobenzothiazolyl group, a benzoxazolyl group, an         isobenzoxazolyl group, a triazolyl group, a tetrazolyl group, an         oxadiazolyl group, a triazinyl group, a dibenzofuranyl group, a         dibenzothiophenyl group, a dibenzosilolyl group, a         benzocarbazolyl group, a dibenzocarbazolyl group, an         imidazopyridinyl group, and an imidazopyrimidinyl group, each         substituted with at least one selected from deuterium, —F, —Cl,         —Br, —I, —CD₃, —CD₂H, —CDH₂, —CF₃, —CF₂H, —CFH₂, a hydroxyl         group, a cyano group, a nitro group, an amino group, an amidino         group, a hydrazine group, a hydrazone group, a carboxylic acid         group or a salt thereof, a sulfonic acid group or a salt         thereof, a phosphoric acid group or a salt thereof, a C₁-C₂₀         alkyl group, a C₁-C₂₀ alkoxy group, a cyclopentyl group, a         cyclohexyl group, a cycloheptyl group, a cyclooctyl group, an         adamantanyl group, a norbornanyl group, a norbornenyl group, a         cyclopentenyl group, a cyclohexenyl group, a cycloheptenyl         group, a phenyl group, a naphthyl group, a fluorenyl group, a         phenanthrenyl group, an anthracenyl group, a fluoranthenyl         group, a triphenylenyl group, a pyrenyl group, a chrysenyl         group, a pyrrolyl group, a thiophenyl group, a furanyl group, an         imidazolyl group, a pyrazolyl group, a thiazolyl group, an         isothiazolyl group, an oxazolyl group, an isoxazolyl group, a         pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a         pyridazinyl group, an isoindolyl group, an indolyl group, an         indazolyl group, a purinyl group, a quinolinyl group, an         isoquinolinyl group, a benzoquinolinyl group, a quinoxalinyl         group, a quinazolinyl group, a cinnolinyl group, a carbazolyl         group, a phenanthrolinyl group, a benzimidazolyl group, a         benzofuranyl group, a benzothiophenyl group, an         isobenzothiazolyl group, a benzoxazolyl group, an         isobenzoxazolyl group, a triazolyl group, a tetrazolyl group, an         oxadiazolyl group, a triazinyl group, a dibenzofuranyl group, a         dibenzothiophenyl group, a dibenzosilolyl group, a         benzocarbazolyl group, a dibenzocarbazolyl group, an         imidazopyridinyl group, an imidazopyrimidinyl group and         —Si(Q₃₃)(Q₃₄)(Q₃₅); and     -   —N(Q₁)(Q₂), —Si(Q₃)(Q₄)(Q₅), —B(Q₆)(Q₇) and —P(═O)(Q₈)(Q₉);     -   wherein Q₁ to Q₉ and Q₃₃ to Q₃₅ are each the same as described         in connection with Q₃₁.

In an embodiment, the R₁ to R₄, R₇, R₈, R′ and R″ are each independently selected from:

-   -   hydrogen, deuterium, —F, a cyano group, a nitro group, —SF₅, a         methyl group, an ethyl group, an n-propyl group, an iso-propyl         group, an n-butyl group, an iso-butyl group, a sec-butyl group,         a tert-butyl group, an n-pentyl group, an iso-pentyl group, a         sec-pentyl group, a tert-pentyl group, an n-hexyl group, an         iso-hexyl group, a sec-hexyl group, a tert-hexyl group, an         n-heptyl group, an iso-heptyl group, a sec-heptyl group, a         tert-heptyl group, an n-octyl group, an iso-octyl group, a         sec-octyl group, a tert-octyl group, an n-nonyl group, an         iso-nonyl group, a sec-nonyl group, a tert-nonyl group, an         n-decyl group, an iso-decyl group, a sec-decyl group, a         tert-decyl group, a methoxy group, an ethoxy group, a propoxy         group, a butoxy group, a pentoxy group, a cyclopentyl group, a         cyclohexyl group, a cycloheptyl group, a cyclooctyl group, an         adamantanyl group, a norbornanyl group, a norbornenyl group, a         cyclopentenyl group, a cyclohexenyl group, a cycloheptenyl         group, a phenyl group, a naphthyl group, a pyridinyl group, a         pyrimidinyl group, a fluorenyl group, a carbazolyl group, a         dibenzofuranyl group, a dibenzothiophenyl group, and a         dibenzosilolyl group;     -   a methyl group, an ethyl group, an n-propyl group, an iso-propyl         group, an n-butyl group, an iso-butyl group, a sec-butyl group,         a tert-butyl group, an n-pentyl group, an iso-pentyl group, a         sec-pentyl group, a tert-pentyl group, an n-hexyl group, an         iso-hexyl group, a sec-hexyl group, a tert-hexyl group, an         n-heptyl group, an iso-heptyl group, a sec-heptyl group, a         tert-heptyl group, an n-octyl group, an iso-octyl group, a         sec-octyl group, a tert-octyl group, an n-nonyl group, an         iso-nonyl group, a sec-nonyl group, a tert-nonyl group, an         n-decyl group, an iso-decyl group, a sec-decyl group, a         tert-decyl group, a methoxy group, an ethoxy group, a propoxy         group, a butoxy group, a pentoxy group, a cyclopentyl group, a         cyclohexyl group, a cycloheptyl group, a cyclooctyl group, an         adamantanyl group, a norbornanyl group, a norbornenyl group, a         cyclopentenyl group, a cyclohexenyl group, a cycloheptenyl         group, a phenyl group, a naphthyl group, a pyridinyl group, a         pyrimidinyl group, a fluorenyl group, a carbazolyl group, a         dibenzofuranyl group, a dibenzothiophenyl group, and a         dibenzosilolyl group, each substituted with at least one         selected from deuterium, —F, —CD₃, —CD₂H, —CDH₂, —CF₃, —CF₂H,         —CFH₂, a cyano group, a nitro group, a C₁-C₁₀ alkyl group, a         C₁-C₁₀ alkoxy group, a cyclopentyl group, a cyclohexyl group, a         cycloheptyl group, a cyclooctyl group, an adamantanyl group, a         norbornanyl group, a norbornenyl group, a cyclopentenyl group, a         cyclohexenyl group, a cycloheptenyl group, a phenyl group, a         naphthyl group, a pyridinyl group, a pyrimidinyl group, a         fluorenyl group, a carbazolyl group, a dibenzofuranyl group, a         dibenzothiophenyl group, a dibenzosilolyl group, and         —Si(Q₃₃)(Q₃₄)(Q₃₅); and     -   —N(Q₁)(Q₂), —Si(Q₃)(Q₄)(Q₅), —B(Q₆)(Q₇) and —P(═O)(Q₈)(Q₉),     -   wherein Q₁ to Q₉ and Q₃₃ to Q₃₅ may be the same as described         above, but embodiments of the present disclosure are not limited         thereto.

In one or more embodiments, R₁ to R₄, R₇, R₈, R′, and R″ may each independently be selected from hydrogen, deuterium, —F, a cyano group, a nitro group, —SF₅, —CH₃, —CD₃, —CD₂H, —CDH₂, —CF₃, —CF₂H, —CFH₂, —C(CD₃)₃, groups represented by Formulae 9-1 to 9-19, groups represented by Formulae 10-1 to 10-140, —N(Q₁)(Q₂), —Si(Q₃)(Q₄)(Q₅), —B(Q₆)(Q₇) and —P(═O)(Q₈)(Q₉) (wherein Q₁ to Q₉ may each be the same as described above), but embodiments of the present disclosure are not limited thereto:

In Formulae 9-1 to 9-19 and 10-1 to 10-140,

-   -   * indicates a binding site to a neighboring atom,     -   “Ph” indicates a phenyl group, and     -   “TMS” indicates a trimethylsilyl group.

c1 to c4 and c7 in Formula 1 respectively indicate the numbers of R₁ to R₄ and R₇, and may each independently be an integer from 1 to 5. When c1 is two or more, two or more of groups R₁ may be identical to or different from each other. c2 to c4 and c7 are the same as described in connection with c1.

In one or more embodiments, c1 to c4 and c7 in Formula 1 may be 1 or 2, but embodiments of the present disclosure are not limited thereto.

Z₁ to Z₄ in Formula 1 may each independently be a cyano group (CN)-containing group.

The cyano group-containing group may be

-   -   a cyano group; or     -   a first group substituted with at least one cyano group;     -   the first group may be selected from a substituted or         unsubstituted C₁-C₆₀ alkyl group, a substituted or unsubstituted         C₂-C₆₀ alkenyl group, a substituted or unsubstituted C₂-C₆₀         alkynyl group, a substituted or unsubstituted C₁-C₆₀ alkoxy         group, a substituted or unsubstituted C₃-C₁₀ cycloalkyl group, a         substituted or unsubstituted C₁-C₁₀ heterocycloalkyl group, a         substituted or unsubstituted C₃-C₁₀ cycloalkenyl group, a         substituted or unsubstituted C₁-C₁₀ heterocycloalkenyl group, a         substituted or unsubstituted C₆-C₆₀ aryl group, a substituted or         unsubstituted C₆-C₆₀ aryloxy group, a substituted or         unsubstituted C₆-C₆₀ arylthio group, a substituted or         unsubstituted C₁-C₆₀ heteroaryl group, a substituted or         unsubstituted monovalent non-aromatic condensed polycyclic         group, and a substituted or unsubstituted monovalent         non-aromatic condensed heteropolycyclic group.

In an embodiment, the first group may be the same as described in connection with R₁. For example, the first group may be selected from —SF₅, —CH₃, —CD₃, —CD₂H, —CDH₂, —CF₃, —CF₂H, —CFH₂, —C(CD₃)₃, groups represented by Formulae 9-1 to 9-19, groups represented by Formulae 10-1 to 10-140, —N(Q₁)(Q₂), —Si(Q₃)(Q₄)(Q₅), —B(Q₆)(Q₇), and —P(═O)(Q₈)(Q₉), but embodiments of the present disclosure are not limited thereto.

When the cyano group-containing group is “the first group substituted with at least one a cyano group” and the first group is *—CH₃, it would be understood through the present specification that the cyano group-containing group includes *—C(CN)₃, *—CH(CN)₂, and *—CH₂(CN).

In an embodiment, the cyano group-containing group may be a cyano group.

In Formula 1, a1 to a4 indicate the numbers of *-[(L₁)_(b1)-(R₁)_(c1)], *-[(L₂)_(b2)-(R₂)_(c2)], -[(L₃)_(b3)-(R₃)_(c3)], and *-[(L₄)_(b4)-(R₄)_(c4)], respectively, and n1, n2, n3, and n4 indicate the numbers of Z₁ to Z₄, respectively, and may each independently be an integer from 0 to 20. When a1 is two or more, two or more groups *-[(L₁)_(b1)-(R₁)_(c1)] may be identical to or different from each other, when a2 is two or more, two or more groups *-[(L₂)_(b2)-(R₂)_(c2)] may be identical to or different from each other, when a3 is two or more, two or more groups *-[(L₃)_(b3)-(R₃)_(c3)] may be identical to or different from each other, when a4 is two or more, two or more groups *-[(L₄)_(b4)-(R₄)_(c4)] may be identical to or different from each other, when n1 is two or more, two or more groups Z₁ may be identical to or different from each other, when n2 is two or more, two or more groups Z₂ may be identical to or different from each other, when n3 is two or more, two or more groups Z₃ may be identical to or different from each other, and when n4 is two or more, two or more groups Z₄ may be identical to or different from each other.

In Formula 1, i) two of a plurality of neighboring groups R₁ may optionally be linked to form a substituted or unsubstituted C₅-C₃₀ carbocyclic group or a substituted or unsubstituted C₁-C₃₀ heterocyclic group, ii) two of a plurality of neighboring groups R₂ may optionally be linked to form a substituted or unsubstituted C₅-C₃₀ carbocyclic group or a substituted or unsubstituted C₁-C₃₀ heterocyclic group, iii) two of a plurality of neighboring groups R₃ may optionally be linked to form a substituted or unsubstituted C₅-C₃₀ carbocyclic group or a substituted or unsubstituted C₁-C₃₀ heterocyclic group, iv) two of a plurality of neighboring groups R₄ may optionally be linked to form a substituted or unsubstituted C₅-C₃₀ carbocyclic group or a substituted or unsubstituted C₁-C₃₀ heterocyclic group, v) two or more selected from groups R₁ to R₄, and R₇ and R₈ may optionally be linked to form a substituted or unsubstituted C₅-C₃₀ carbocyclic group or a substituted or unsubstituted C₁-C₃₀ heterocyclic group.

For example, in Formula 1, i) a substituted or unsubstituted C₅-C₃₀ carbocyclic group or a substituted or unsubstituted C₁-C₃₀ heterocyclic group, formed by bonding two of a plurality of neighboring groups R₁, ii) a substituted or unsubstituted C₅-C₃₀ carbocyclic group or a substituted or unsubstituted C₁-C₃₀ heterocyclic group, formed by bonding two of a plurality of neighboring groups R₂, iii) a substituted or unsubstituted C₅-C₃₀ carbocyclic group or a substituted or unsubstituted C₁-C₃₀ heterocyclic group, formed by bonding two of a plurality of neighboring groups R₃, iv) a substituted or unsubstituted C₅-C₃₀ carbocyclic group or a substituted or unsubstituted C₁-C₃₀ heterocyclic group, formed by bonding two of a plurality of neighboring groups R₄, and v) a substituted or unsubstituted C₅-C₃₀ carbocyclic group or a substituted or unsubstituted C₁-C₃₀ heterocyclic group, formed by bonding two or more selected from R₁ to R₄, R₇, and R₈, may each independently be selected from:

-   -   a pentadiene group, a cyclohexane group, a cycloheptane group,         an adamantane group, a bicycle-heptane group, a bicycle-octane         group, a benzene group, a pyridine group, a pyrimidine group, a         pyrazine group, a pyridazine group, a naphthalene group, an         anthracene group, a tetracene group, a phenanthrene group, a         dihydronaphthalene group, a phenalene group, a benzothiophene         group, a benzofuran group, an indene group, an indole group, a         benzosilole group, an azabenzothiophene group, an azabenzofuran         group, an azaindene group, an azaindole group, and an         azabenzosilole group; and     -   a pentadiene group, a cyclohexane group, a cycloheptane group,         an adamantane group, a bicycle-heptane group, a bicycle-octane         group, a benzene group, a pyridine group, a pyrimidine group, a         pyrazine group, a pyridazine group, a naphthalene group, an         anthracene group, a tetracene group, a phenanthrene group, a         dihydronaphthalene group, a phenalene group, a benzothiophene         group, a benzofuran group, an indene group, an indole group, a         benzosilole group, an azabenzothiophene group, an azabenzofuran         group, an azaindene group, an azaindole group, and an         azabenzosilole group, each substituted with at least one         selected from at least one R_(10a);     -   but embodiments of the present disclosure are not limited         thereto.

R_(10a) may be the same as described in connection with R₁.

“An azabenzothiophene, an azabenzofuran, an azaindene, an azaindole, an azabenzosilole, an azadibenzothiophene, an azadibenzofuran, an azafluorene, an azacarbazole, and an azadibenzosilole” each have the same ring system as “a benzothiophene, a benzofuran, an indene, an indole, a benzosilole, a dibenzothiophene, a dibenzofuran, a fluorene, a carbazole, and a dibenzosilole,” respectively, and each further contain a hetero ring in which at least one of ring-forming carbon atoms is substituted with nitrogen.

In Formula 1,

-   -   i) when X₅₁ is O, S, C(═O), or N, the sum of n1, n2, n3, and n4         may be 1 or more (for example, 1, 2, 3, 4, or 5),     -   ii) when X₅₁ is N[(L₇)_(b7)-(R₇)_(c7)], C(R₇), Si(R₇), or         Ge(R₇), R₇ may be a cyano group-containing group or the sum of         n1, n2, n3, and n4 may be 1 or more (for example, 1, 2, 3, 4, or         5), and     -   iii) when X₅₁ is C(R₇)(R₈), Si(R₇)(R₈), or Ge(R₇)(R₈), at least         one selected from R₇ and R₈ may be a cyano group-containing         group or the sum of n1, n2, n3, and n4 may be 1 or more (for         example, 1, 2, 3, 4, or 5).

That is, the organometallic compound represented by Formula 1 essentially includes at least one cyano group-containing group as defined herein.

In an embodiment, the sum of n1, n2, n3, and n4 in Formula 1 may be 1, 2, 3, or 4, for example, 1 or 2. That is, the number of cyano group-containing groups included in Formula 1 may be 1, 2, 3, or 4, for example, 1 or 2, but embodiments of the present disclosure are not limited thereto.

In one or more embodiments, in Formula 1,

-   -   i) n1=n2=n3=0, and n4=1,     -   ii) n1=n2=n4=0, and n3=1,     -   iii) n1=n3=n4=0, and n2=1,     -   iv) n2=n3=n4=0, and n1=1,     -   v) n1=n2=0, and n3=n4=1,     -   vi) n2=n3=0, and n1=n4=1,     -   vii) n2=n4=0, and n1=n3=1, or     -   viii) n1=n3=0, and n2=n4=1, but embodiments of the present         disclosure are not limited thereto.

In one or more embodiments, in Formula 1,

-   -   i) X₁ is a chemical bond, and a moiety represented by

may be a group represented by Formula CY1-B, or

-   -   ii) X₁ may be O, S, N(R′), P(R′), B(R′), C(R′)(R″), Si(R′)(R″),         or N(R′)(R″), and a moiety represented by

may be a group represented by Formula CY1-A:

In Formulae CY1-A and CY1-B, Y₁, CY₁, L₁, b1, R₁, c1, a1, Z₁, and n1 are the same as described above, Y₂ and Y₆ may each independently be N or C; and a bond between Y₁ and Y₂, a bond between Y₁ and Y₆ and a bond between Y₆ and Y₂ may each be a chemical bond (for example, a single bond, a double bond, or a bond constituting a carbene ligand, or the like).

In one or more embodiments, in Formula 1, a moiety represented by

may be a group represented by Formulae CY1-1 to CY1-40:

In Formulae CY1-1 to CY1-40,

-   -   Y₁, R₁, Z₁, and n1 are the same as described above, n1 is 0, 1,         or 2,     -   X₁₉ is C(R_(19a))(R_(19b)), N[(L₁₉)_(b19)-(R₁₉)_(c19)], O, S, or         Si(R_(19a))(R_(19b)),     -   L₁₉ may be the same as explained in connection with L₁,     -   b19 and c19 are the same as described in connection with b1 and         c1,     -   R₁₁ to R₁₉, R_(19a), and R_(19b) may be the same as described in         connection with R₁,     -   a12 may be an integer from 0 to 2,     -   a13 may be an integer from 0 to 3,     -   a14 may be an integer from 0 to 4,     -   a15 may be an integer from 0 to 5,     -   a16 may be an integer from 0 to 6,     -   a17 may be an integer from 0 to 7,     -   *′ indicates a binding site to M in Formula 1, and     -   * indicates a binding site to CY₅ in Formula 1.

In one or more embodiments, in Formula 1, a moiety represented by

may be a group represented by Formulae CY2-1 to CY2-20:

In Formulae CY2-1 to CY2-20,

-   -   R₂, Z₂, and n2 may be the same as described above, n2 may be 0,         1, or 2,     -   X₅₁ in Formulae CY2-1 to CY2-4 may be O, S,         N-[(L₇)_(b7)-(R₇)_(c7)], C(R₇)(R₈), Si(R₇)(R₈), Ge(R₇)(R₈), or         C(═O),     -   X₅₁ in Formulae CY2-5 to CY2-20 may be N, C(R₇), Si(R₇), or         Ge(R₇),     -   L₇, b7, R₇, and c7 may be the same as described above,     -   a22 may be an integer from 0 to 2,     -   a23 may be an integer from 0 to 3,     -   indicates a binding site to CY₁ in Formula 1,     -   *′ indicates a binding site to M in Formula 1, and     -   *″ indicates a binding site to CY₃ in Formula 1.

In one or more embodiments, in Formula 1, a moiety represented by

may be a group represented by one of Formulae CY3-1 to CY3-12:

In Formulae CY3-1 to CY3-12,

-   -   X₃, R₃, Z₃, and n3 may be the same as described above, n3 is 0,         1, or 2,     -   X₃₉ may be C(R_(39a))(R_(39b)), N[(L₃₉)_(b39)-(R₃₉)_(c39)], O,         S, or Si(R_(39a))(R_(39b)),     -   L₃₉ may be the same as explained in connection with L₃;     -   b39 and c39 may be the same as described in connection with b3         and c3     -   R_(39a) and R_(39b) may be the same as described in connection         with R₃,     -   a32 may be an integer from 0 to 2,     -   a33 may be an integer from 0 to 3,     -   a34 may be an integer from 0 to 4,     -   a35 may be an integer from 0 to 5,     -   * indicates a binding site to CY₄ in Formula 1,     -   *′ indicates a binding site to M in Formula 1, and     -   *″ indicates a binding site to CY₂ in Formula 1.

In one or more embodiments, in Formula 1, a moiety represented by

may be a group represented by one of Formulae CY4-1 to CY4-26:

In Formulae CY4-1 to CY4-26,

-   -   X₄, R₄, Z₄, and n4 may be the same as described above, n4 may be         0, 1, or 2,     -   X₄₉ may be C(R_(49a))(R_(49b)), N[(L₄₉)_(b49)-(R₄₉)_(c49)], O,         S, or Si(R_(49a))(R_(49b)),     -   L₄₉ may be the same as explained in connection with L₄;     -   b49 and c49 may be the same as described in connection with b4         and c4,     -   R₄₁ to R₄₉, R_(49a), and R_(49b) may be the same as described in         connection with R₄,     -   a42 may be an integer from 0 to 2,     -   a43 may be an integer from 0 to 3,     -   a44 may be an integer from 0 to 4,     -   a45 may be an integer from 0 to 5,     -   a46 may be an integer from 0 to 6,     -   * indicates a binding site to CY₃ in Formula 1, and     -   *′ indicates a binding site to M in Formula 1.

In one or more embodiments, regarding Formula 1,

a moiety represented by

may be a group represented by Formulae CY1(1) to CY1(18) and CY1-CN(1) to CY1-CN(12), and(or)

a moiety represented by

may be a group represented by Formulae CY2(1) to CY2(20) and CY2-CN(1) to CY2-CN(15), and(or)

a moiety represented by

may be a group represented by Formulae CY3(1) to CY3(12) and CY3-CN(1) to CY3-CN(8), and(or)

a moiety represented by

may be a group represented by Formulae CY4(1) to CY4(10) and CY4-CN(1) to CY4-CN(12), but embodiments of the present disclosure are not limited thereto:

In Formulae CY1(1) to CY1(18), CY1-CN(1) to CY1-CN(12), CY2(1) to CY2(20), CY2-CN(1) to CY2-CN(15), CY3(1) to CY3(12), CY3-CN(1) to CY3-CN(8), CY4(1) to CY4(10), and CY4-CN(1) to CY4-CN(12),

-   -   X₂ to X₄, Y₁, R₁ to R₄, and Z₁ to Z₄ may be the same as         described above,     -   R_(1a) to R_(1d) may be the same as described in connection with         R₁,     -   X₃₉ may be C(R_(39a))(R_(39b)), N[(L₃₉)_(b39)-(R₃₉)_(c39)], O,         S, or Si(R_(39a))(R_(39b)),     -   L₃₉ may be the same as explained in connection with L₃;     -   b39 and c39 may be the same as described in connection with b3         and c3,     -   R_(3a), R_(3b), R_(39a), and R_(39b) may be the same as         described in connection with R₃,     -   R_(4a) to R_(4d) may be the same as described in connection with         R₄,     -   R₁ to R₄, R_(1a) to R_(1d), R_(3a), R_(3b), and R_(4a) to R_(4d)         may each not be hydrogen,     -   *′ indicates a binding site to M in Formula 1,     -   *′ in Formulae CY1(1) to CY1(18) and CY1-CN(1) to CY1-CN(12)         indicates a binding site to CY₅ in Formula 1,     -   * in Formulae CY2(1) to CY2(20) and CY2-CN(1) to CY2-CN(15)         indicates a binding site to CY₁ in Formula 1,     -   *″ in Formulae CY2(1) to CY2(20) and CY2-CN(1) to CY2-CN(15)         indicates a binding site to CY₃ in Formula 1,     -   *″ in Formulae CY3(1) to CY3(12) and CY3-CN(1) to CY3-CN(8)         indicates a binding site to CY₂ in Formula 1,     -   * in Formulae CY3(1) to CY3(12) and CY3-CN(1) to CY3-CN(8)         indicates a binding site to CY₄ in Formula 1, and     -   * in Formulae CY4(1) to CY4(10) and CY4-CN(1) to CY4-CN(12)         indicates a binding site to CY₃ in Formula 1.

For example, the organometallic compound may be one of Compounds 1 to 190, but embodiments of the present disclosure are not limited thereto:

Formula 1 has a 5-membered ring represented by CY₅, and a cyclometalated ring formed by CY₅, CY₂, CY₃, and M in Formula 1 is a 6-membered ring. Due to this structure, a binding angle between tetradentate ligand and metal in Formula 1 is stable, and accordingly, the molecular stability of the organometallic compound represented by Formula 1 may be improved.

Also, in Formula 1, i) when X₅₁ is O, S, C(═O), or N, the sum of n1, n2, n3, and n4 is 1 or more, ii) when X₅₁ is N[(L₇)_(b7)-(R₇)C₇], C(R₇), Si(R₇), or Ge(R₇), R₇ is a cyano group-containing group or the sum of n1, n2, n3, and n4 is 1 or more, and iii) when X₅₁ is C(R₇)(R₈), Si(R₇)(R₈), or Ge(R₇)(R₈), at least one selected from R₇ and R₈ is a cyano group-containing group or the sum of n1, n2, n3, and n4 is 1 or more. That is, the organometallic compound represented by Formula 1 essentially includes at least one cyano group-containing group as defined herein. Accordingly, charge-transfer characteristics of the organometallic compound are improved, and thus, an electronic device, for example, an organic light-emitting device, in which the organometallic compound is used, may have an improved luminescent efficiency and an easily controllable-emission wavelength band.

For example, the highest occupied molecular orbital (HOMO), lowest unoccupied molecular orbital (LUMO), singlet (Si), and triplet (T₁) energy levels of Compounds 61, 123, 124, 128, and 158 were calculated by using a DFT method of the Gaussian program [structurally optimized at the level of B3LYP, 6-31G(d,p)]. The evaluation results are shown in Table 1 below.

TABLE 1 HOMO LUMO T₁ energy level Compound No. (eV) (eV) (eV) 61 −5.014 −2.453 1.961 123 −4.920 −2.419 1.906 124 −4.866 −2.396 1.878 128 −4.866 −2.318 1.977 158 −4.617 −2.438 1.639

From the data in Table 1, it is confirmed that the organometallic compound represented by Formula 1 has such electric characteristics that are suitable for use in an electric device, for example, for use as a dopant for an organic light-emitting device.

Synthesis methods of the organometallic compound represented by Formula 1 may be recognizable by one of ordinary skill in the art by referring to Synthesis Examples provided below.

The organometallic compound represented by Formula 1 is suitable for use in an organic layer of an organic light-emitting device, for example, for use as a dopant in an emission layer of the organic layer.

Thus, another aspect of the present disclosure provides an organic light-emitting device that includes:

-   -   a first electrode;     -   a second electrode; and     -   an organic layer that is disposed between the first electrode         and the second electrode,     -   wherein the organic layer includes an emission layer and at         least one organometallic compound represented by Formula 1.

The organic light-emitting device may have, due to the inclusion of an organic layer including the organometallic compound represented by Formula 1, a low driving voltage, high efficiency, high power, high quantum efficiency, a long lifespan, a low roll-off ratio, and excellent color purity.

The organometallic compound of Formula 1 may be used between a pair of electrodes of an organic light-emitting device. For example, the organometallic compound represented by Formula 1 may be included in the emission layer. In this regard, the organometallic compound may act as a dopant, and the emission layer may further include a host (that is, an amount of the organometallic compound represented by Formula 1 is smaller than an amount of the host).

The expression “(an organic layer) includes at least one of organometallic compounds” used herein may include a case in which “(an organic layer) includes identical organometallic compounds represented by Formula 1” and a case in which “(an organic layer) includes two or more different organometallic compounds represented by Formula 1.”

For example, the organic layer may include, as the organometallic compound, only Compound 1. In this regard, Compound 1 may be included in an emission layer of the organic light-emitting device. In one or more embodiments, the organic layer may include, as the organometallic compound, Compound 1 and Compound 2. In this regard, Compound 1 and Compound 2 may be included in an identical layer (for example, Compound 1 and Compound 2 all may be included in an emission layer).

The first electrode may be an anode, which is a hole injection electrode, and the second electrode may be a cathode, which is an electron injection electrode; or the first electrode may be a cathode, which is an electron injection electrode, and the second electrode may be an anode, which is a hole injection electrode.

In an embodiment, in the organic light-emitting device, the first electrode is an anode, and the second electrode is a cathode, and the organic layer further includes a hole transport region disposed between the first electrode and the emission layer and an electron transport region disposed between the emission layer and the second electrode, wherein the hole transport region includes a hole injection layer, a hole transport layer, an electron blocking layer, or any combination thereof, and wherein the electron transport region includes a hole blocking layer, an electron transport layer, an electron injection layer, or any combination thereof.

The term “organic layer” as used herein refers to a single layer and/or a plurality of layers disposed between the first electrode and the second electrode of the organic light-emitting device. The “organic layer” may include, in addition to an organic compound, an organometallic complex including metal.

The FIG. 1s a schematic view of an organic light-emitting device 10 according to an embodiment. Hereinafter, the structure of an organic light-emitting device according to an embodiment and a method of manufacturing an organic light-emitting device according to an embodiment will be described in connection with the FIGURE. The organic light-emitting device 10 includes a first electrode 11, an organic layer 15, and a second electrode 19, which are sequentially stacked.

A substrate may be additionally located under the first electrode 11 or above the second electrode 19. For use as the substrate, any substrate that is used in general organic light-emitting devices may be used, and the substrate may be a glass substrate or a transparent plastic substrate, each having excellent mechanical strength, thermal stability, transparency, surface smoothness, ease of handling, and water resistance.

The first electrode 11 may be formed by depositing or sputtering a material for forming the first electrode 11 on the substrate. The first electrode 11 may be an anode. The material for forming the first electrode 11 may be selected from materials with a high work function to facilitate hole injection. The first electrode 11 may be a reflective electrode, a semi-transmissive electrode, or a transmissive electrode. The material for forming the first electrode may be, for example, indium tin oxide (ITO), indium zinc oxide (IZO), tin oxide (SnO2), and zinc oxide (ZnO). In one or more embodiments, magnesium (Mg), aluminum (Al), aluminum-lithium (Al—Li), calcium (Ca), magnesium-indium (Mg—In), or magnesium-silver (Mg—Ag) may be used as the material for forming the first electrode.

The first electrode 11 may have a single-layered structure or a multi-layered structure including two or more layers. For example, the first electrode 11 may have a three-layered structure of ITO/Ag/ITO, but the structure of the first electrode 110 is not limited thereto.

The organic layer 15 is located on the first electrode 11.

The organic layer 15 may include a hole transport region, an emission layer, and an electron transport region.

The hole transport region may be disposed between the first electrode 11 and the emission layer.

The hole transport region may include a hole injection layer, a hole transport layer, an electron blocking layer, a buffer layer, or any combination thereof.

The hole transport region may include only either a hole injection layer or a hole transport layer. In one or more embodiments, the hole transport region may have a hole injection layer/hole transport layer structure or a hole injection layer/hole transport layer/electron blocking layer structure, which are sequentially stacked in this stated order from the first electrode 11.

A hole injection layer may be formed on the first electrode 11 by using one or more suitable methods selected from vacuum deposition, spin coating, casting, or Langmuir-Blodgett (LB) deposition.

When a hole injection layer is formed by vacuum deposition, the deposition conditions may vary depending on a material that is used to form the hole injection layer, and the structure and thermal characteristics of the hole injection layer. For example, the deposition conditions may include a deposition temperature of about 100 to about 500° C., a vacuum pressure of about 10⁻⁸ to about 10⁻³ torr, and a deposition rate of about 0.01 to about 100 Å/sec. However, the deposition conditions are not limited thereto.

When the hole injection layer is formed using spin coating, coating conditions may vary according to the material used to form the hole injection layer, and the structure and thermal properties of the hole injection layer. For example, a coating speed may be from about 2,000 revolutions per minute (rpm) to about 5,000 rpm, and a temperature at which a heat treatment is performed to remove a solvent after coating may be from about 80° C. to about 200° C. However, the coating conditions are not limited thereto.

Conditions for forming a hole transport layer and an electron blocking layer may be understood by referring to conditions for forming the hole injection layer.

The hole transport region may include at least one selected from m-MTDATA, TDATA, 2-TNATA, NPB, β-NPB, TPD, Spiro-TPD, Spiro-NPB, methylated-NPB, TAPC, HMTPD, 4,4′,4″-tris(N-carbazolyl)triphenylamine (TCTA), polyaniline/dodecylbenzenesulfonic acid (PANI/DBSA), poly(3,4-ethylenedioxythiophene)/poly(4-styrenesulfonate) (PEDOT/PSS), polyaniline/camphor sulfonicacid (PANI/CSA), polyaniline/poly(4-styrenesulfonate) (PANI/PSS), a compound represented by Formula 201 below, and a compound represented by Formula 202 below:

Ar₁₀₁ and Ar₁₀₂ in Formula 201 may each independently be selected from:

a phenylene group, a pentalenylene group, an indenylene group, a naphthylene group, an azulenylene group, a heptalenylene group, an acenaphthylene group, a fluorenylene group, a phenalenylene group, a phenanthrenylene group, an anthracenylene group, a fluoranthenylene group, a triphenylenylene group, a pyrenylene group, a chrysenylenylene group, a naphthacenylene group, a picenylene group, a perylenylene group, and a pentacenylene group; and

a phenylene group, a pentalenylene group, an indenylene group, a naphthylene group, an azulenylene group, a heptalenylene group, an acenaphthylene group, a fluorenylene group, a phenalenylene group, a phenanthrenylene group, an anthracenylene group, a fluoranthenylene group, a triphenylenylene group, a pyrenylene group, a chrysenylenylene group, a naphthacenylene group, a picenylene group, a perylenylene group, or a pentacenylene group, each substituted with at least one selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, a C₁-C₆₀ alkoxy group, a C₃-C₁₀ cycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, a monovalent non-aromatic condensed polycyclic group, and a monovalent non-aromatic condensed heteropolycyclic group.

In Formula 201, xa and xb may each independently be an integer from 0 to 5, or 0, 1, or 2. For example, xa is 1 and xb is 0, but xa and xb are not limited thereto.

R₁₀₁ to R₁₀₈, R₁₁₁ to R₁₁₉, and R₁₂₁ to R₁₂₄ in Formulae 201 and 202 may each independently be selected from:

hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C₁-C₁₀ alkyl group (for example, a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, and so on), and a C₁-C₁₀ alkoxy group (for example, a methoxy group, an ethoxy group, a propoxy group, a butoxy group, a pentoxy group, and so on);

a C₁-C₁₀ alkyl group and a C₁-C₁₀ alkoxy group, each substituted with at least one selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, and a phosphoric acid group or a salt thereof;

a phenyl group, a naphthyl group, an anthracenyl group, a fluorenyl group, and a pyrenyl group; and

a phenyl group, a naphthyl group, an anthracenyl group, a fluorenyl group, and a pyrenyl group, each substituted with at least one selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C₁-C₁₀ alkyl group, and a C₁-C₁₀ alkoxy group, but they are not limited thereto.

but embodiments of the present disclosure are not limited thereto.

R₁₀₉ in Formula 201 may be selected from:

a phenyl group, a naphthyl group, an anthracenyl group, and a pyridinyl group; and

a phenyl group, a naphthyl group, an anthracenyl group, and a pyridinyl group, each substituted with at least one selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, a phenyl group, a naphthyl group, an anthracenyl group, and a pyridinyl group.

According to an embodiment, the compound represented by Formula 201 may be represented by Formula 201A, but embodiments of the present disclosure are not limited thereto:

R₁₀₁, R₁₁₁, R₁₁₂, and R₁₀₉ in Formula 201A may be understood by referring to the description provided herein.

For example, the compound represented by Formula 201, and the compound represented by Formula 202 may include compounds HT1 to HT20 illustrated below, but are not limited thereto:

A thickness of the hole transport region may be in a range of about 100 Å to about 10,000 Å, for example, about 100 Å to about 1,000 Å. When the hole transport region includes at least one of a hole injection layer and a hole transport layer, the thickness of the hole injection layer may be in a range of about 100 Å to about 10,000 Å, and for example, about 100 Å to about 1,000 Å, and the thickness of the hole transport layer may be in a range of about 50 Å to about 2,000 Å, and for example, about 100 Å to about 1,500 Å. While not wishing to be bound by theory, it is understood that when the thicknesses of the hole transport region, the hole injection layer, and the hole transport layer are within these ranges, satisfactory hole transporting characteristics may be obtained without a substantial increase in driving voltage.

The hole transport region may further include, in addition to these materials, a charge-generation material for the improvement of conductive properties. The charge-generation material may be homogeneously or non-homogeneously dispersed in the hole transport region.

The charge-generation material may be, for example, a p-dopant. The p-dopant may be one selected from a quinone derivative, a metal oxide, and a cyano group-containing compound, but embodiments of the present disclosure are not limited thereto. Non-limiting examples of the p-dopant are a quinone derivative, such as tetracyanoquinonedimethane (TCNQ) or 2,3,5,6-tetrafluoro-tetracyano-1,4-benzoquinonedimethane (F4-TCNQ); a metal oxide, such as a tungsten oxide or a molybdenium oxide; and a cyano group-containing compound, such as Compound HT-D1 below, but are not limited thereto.

The hole transport region may include a buffer layer.

Also, the buffer layer may compensate for an optical resonance distance depending on a wavelength of light emitted from the emission layer, and thus, efficiency of a formed organic light-emitting device may be improved.

Then, an emission layer (EML) may be formed on the hole transport region by vacuum deposition, spin coating, casting, LB deposition, or the like. When the emission layer is formed by vacuum deposition or spin coating, the deposition or coating conditions may be similar to those applied in forming the hole injection layer although the deposition or coating conditions may vary according to a compound that is used to form the emission layer.

Meanwhile, when the hole transport region includes an electron blocking layer, a material for the electron blocking layer may be selected from materials for the hole transport region described above and materials for a host to be explained later. However, the material for the electron blocking layer is not limited thereto. For example, when the hole transport region includes an electron blocking layer, a material for the electron blocking layer may be mCP, which will be explained later.

The emission layer may include a host and a dopant, and the dopant may include the organometallic compound represented by Formula 1.

The host may include at least one selected from TPBi, TBADN, ADN (also referred to as “DNA”), CBP, CDBP, TCP, mCP, Compound H50, and Compound H51:

In one or more embodiments, the host may further include a compound represented by Formula 301 below.

Ar₁₁₁ and Ar₁₁₂ in Formula 301 may each independently be selected from:

a phenylene group, a naphthylene group, a phenanthrenylene group, and a pyrenylene group; and

a phenylene group, a naphthylene group, a phenanthrenylene group, and a pyrenylene group, each substituted with at least one selected from a phenyl group, a naphthyl group, and an anthracenyl group;

Ar₁₁₃ to Ar₁₁₆ in Formula 301 may each independently be selected from:

a C₁-C₁₀ alkyl group, a phenyl group, a naphthyl group, a phenanthrenyl group, and a pyrenyl group; and

a phenyl group, a naphthyl group, a phenanthrenyl group, and a pyrenyl group, each substituted with at least one selected from a phenyl group, a naphthyl group, and an anthracenyl group.

g, h, i, and j in Formula 301 may each independently be an integer from 0 to 4, and may be, for example, 0, 1, or 2.

Ar₁₁₃ to Ar₁₁₆ in Formula 301 may each independently be selected from:

a C₁-C₁₀ alkyl group, substituted with at least one selected from a phenyl group, a naphthyl group, and an anthracenyl group;

a phenyl group, a naphthyl group, an anthracenyl group, a pyrenyl, a phenanthrenyl group, and a fluorenyl group;

a phenyl group, a naphthyl group, an anthracenyl group, a pyrenyl group, a phenanthrenyl group, and a fluorenyl group, each substituted with at least one selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, a C₁-C₆₀ alkoxy group, a phenyl group, a naphthyl group, an anthracenyl group, a pyrenyl group, a phenanthrenyl group, and a fluorenyl group; and

but embodiments of the present disclosure are not limited thereto.

In one or more embodiments, the host may include a compound represented by Formula 302 below:

Ar₁₂₂ to Ar₁₂5 in Formula 302 are the same as described in detail in connection with Ar₁₁₃ in Formula 301.

Ar₁₂₆ and Ar₁₂₇ in Formula 302 may each independently be a C₁-C₁₀ alkyl group (for example, a methyl group, an ethyl group, or a propyl group).

k and l in Formula 302 may each independently be an integer from 0 to 4. For example, k and l may be 0, 1, or 2.

When the organic light-emitting device is a full-color organic light-emitting device, the emission layer may be patterned into a red emission layer, a green emission layer, and a blue emission layer. In one or more embodiments, due to a stacked structure including a red emission layer, a green emission layer, and/or a blue emission layer, the emission layer may emit white light.

When the emission layer includes a host and a dopant, an amount of the dopant may be in a range of about 0.01 parts by weight to about 15 parts by weight based on 100 parts by weight of the host, but embodiments of the present disclosure are not limited thereto.

A thickness of the emission layer may be in a range of about 100 Å to about 1,000 Å, for example, about 200 Å to about 600 Å. While not wishing to be bound by theory, it is understood that when the thickness of the emission layer is within this range, excellent light-emission characteristics may be obtained without a substantial increase in driving voltage.

Then, an electron transport region may be located on the emission layer.

The electron transport region may include a hole blocking layer, an electron transport layer, an electron injection layer, or any combination thereof.

For example, the electron transport region may have a hole blocking layer/electron transport layer/electron injection layer structure or an electron transport layer/electron injection layer structure, but the structure of the electron transport region is not limited thereto. The electron transport layer may have a single-layered structure or a multi-layered structure including two or more different materials.

Conditions for forming the hole blocking layer, the electron transport layer, and the electron injection layer which constitute the electron transport region may be understood by referring to the conditions for forming the hole injection layer.

When the electron transport region includes a hole blocking layer, the hole blocking layer may include, for example, at least one of BCP, Bphen, and BAIq but embodiments of the present disclosure are not limited thereto.

A thickness of the hole blocking layer may be in a range of about 20 Å to about 1,000 Å, for example, about 30 Å to about 300 Å. While not wishing to be bound by theory, it is understood that when the thickness of the hole blocking layer is within these ranges, the hole blocking layer may have improved hole blocking ability without a substantial increase in driving voltage.

The electron transport layer may further include at least one selected from BCP, Bphen, Alq3, BAIq, TAZ, and NTAZ.

In one or more embodiments, the electron transport layer may include at least one of ET1 and ET25, but are not limited thereto:

A thickness of the electron transport may be in a range of about 100 Å to about 1,000 Å, for example, about 150 Å to about 500 Å. While not wishing to be bound by theory, it is understood that when the thickness of the electron transport layer is within the range described above, the electron transport layer may have satisfactory electron transport characteristics without a substantial increase in driving voltage.

Also, the electron transport layer may further include, in addition to the materials described above, a metal-containing material.

The metal-containing material may include a Li complex. The Li complex may include, for example, Compound ET-D1 (lithium quinolate, LiQ) or ET-D2.

The electron transport region may include an electron injection layer (EIL) that promotes flow of electrons from the second electrode 19 thereinto.

The electron injection layer may include at least one selected from LiF, NaCl, CsF, Li₂O, and BaO.

A thickness of the electron injection layer may be in a range of about 1 Å to about 100 Å, for example, about 3 Å to about 90 Å. While not wishing to be bound by theory, it is understood that when the thickness of the electron injection layer is within the range described above, the electron injection layer may have satisfactory electron injection characteristics without a substantial increase in driving voltage.

The second electrode 19 is located on the organic layer 15. The second electrode 19 may be a cathode. A material for forming the second electrode 19 may be selected from metal, an alloy, an electrically conductive compound, and a combination thereof, which have a relatively low work function. For example, lithium (Li), magnesium (Mg), aluminum (Al), aluminum-lithium (Al—Li), calcium (Ca), magnesium-indium (Mg—In), or magnesium-silver (Mg—Ag) may be used as a material for forming the second electrode 19. In one or more embodiments, to manufacture a top-emission type light-emitting device, a transmissive electrode formed using ITO or IZO may be used as the second electrode 19.

Hereinbefore, the organic light-emitting device has been described with reference to the FIGURE, but embodiments of the present disclosure are not limited thereto.

Another aspect of the present disclosure provides a diagnostic composition including at least one organometallic compound represented by Formula 1.

The organometallic compound represented by Formula 1 provides high luminescent efficiency. Accordingly, a diagnostic composition including the organometallic compound may have high diagnostic efficiency.

The diagnostic composition may be used in various applications including a diagnosis kit, a diagnosis reagent, a biosensor, and a biomarker.

The term “C₁-C₆₀ alkyl group” as used herein refers to a linear or branched saturated aliphatic hydrocarbon monovalent group having 1 to 60 carbon atoms, and non-limiting examples thereof include a methyl group, an ethyl group, a propyl group, an iso-butyl group, a sec-butyl group, a tert-butyl group, a pentyl group, an iso-amyl group, and a hexyl group. The term “C₁-C₆₀ alkylene group” as used herein refers to a divalent group having the same structure as the C₁-C₆₀ alkyl group.

The term “C₁-C₆₀ alkoxy group” as used herein refers to a monovalent group represented by —OA₁₀₁ (wherein A₁₀₁ is the C₁-C₆₀ alkyl group), and non-limiting examples thereof include a methoxy group, an ethoxy group, and an iso-propyloxy group.

The term “C₂-C₆₀ alkenyl group” as used herein refers to a hydrocarbon group formed by including at least one carbon-carbon double bond in the middle or at the terminus of the C₂-C₆₀ alkyl group, and examples thereof include an ethenyl group, a propenyl group, and a butenyl group. The term “C₂-C₆₀ alkenylene group” as used herein refers to a divalent group having the same structure as the C₂-C₆₀ alkenyl group.

The term “C₂-C₆₀ alkynyl group” as used herein refers to a hydrocarbon group formed by including at least one carbon-carbon triple bond in the middle or at the terminus of the C₂-C₆₀ alkyl group, and examples thereof include an ethynyl group, and a propynyl group. The term “C₂-C₆₀ alkynylene group” as used herein refers to a divalent group having the same structure as the C₂-C₆₀ alkynyl group.

The term “C₃-C₁₀ cycloalkyl group” as used herein refers to a monovalent saturated hydrocarbon monocyclic group having 3 to 10 carbon atoms, and non-limiting examples thereof include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, and a cycloheptyl group. The term “C₃-C₁₀ cycloalkylene group” as used herein refers to a divalent group having the same structure as the C₃-C₁₀ cycloalkyl group.

The term “C₁-C₁₀ heterocycloalkyl group” as used herein refers to a monovalent saturated monocyclic group having at least one heteroatom selected from N, O, P, Si and S as a ring-forming atom and 1 to 10 carbon atoms, and non-limiting examples thereof include a tetrahydrofuranyl group, and a tetrahydrothiophenyl group. The term “C₁-C₁₀ heterocycloalkylene group” as used herein refers to a divalent group having the same structure as the C₁-C₁₀ heterocycloalkyl group.

The term “C₃-C₁₀ cycloalkenyl group” as used herein refers to a monovalent monocyclic group that has 3 to 10 carbon atoms, that has at least one carbon-carbon double bond in the ring thereof, and that is not aromatic. Non-limiting examples thereof include a cyclopentenyl group, a cyclohexenyl group, and a cycloheptenyl group. The term “C₃-C₁₀ cycloalkenylene group” as used herein refers to a divalent group having the same structure as the C₃-C₁₀ cycloalkenyl group.

The term “C₁-C₁₀ heterocycloalkenyl group” as used herein refers to a monovalent monocyclic group that has at least one heteroatom selected from N, O, P, Si, and S as a ring-forming atom, 1 to 10 carbon atoms, and that has at least one carbon-carbon double bond in its ring. Examples of the C₁-C₁₀ heterocycloalkenyl group are a 2,3-dihydrofuranyl group, and a 2,3-dihydrothiophenyl group. The term “C₁-C₁₀ heterocycloalkenylene group” as used herein refers to a divalent group having the same structure as the C₁-C₁₀ heterocycloalkenyl group.

The term “C₆-C₆₀ aryl group” as used herein refers to a monovalent group having a carbocyclic aromatic system having 6 to 60 carbon atoms, and the term “C₆-C₆₀ arylene group” as used herein refers to a divalent group having a carbocyclic aromatic system having 6 to 60 carbon atoms. Non-limiting examples of the C₆-C₆₀ aryl group include a phenyl group, a naphthyl group, an anthracenyl group, a phenanthrenyl group, a pyrenyl group, and a chrysenyl group. When the C₆-C₆₀ aryl group and the C₆-C₆₀ arylene group each include two or more rings, the rings may be fused to each other.

The term “C₁-C₆₀ heteroaryl group” as used herein refers to a monovalent group having a carbocyclic aromatic system that has at least one heteroatom selected from N, O, P, Si, and S as a ring-forming atom, and 1 to 60 carbon atoms. The term “C₁-C₆₀ heteroarylene group” as used herein refers to a divalent group having a carbocyclic aromatic system that has at least one heteroatom selected from N, O, P, and S as a ring-forming atom, and 1 to 60 carbon atoms. Non-limiting examples of the C₁-C₆₀ heteroaryl group include a pyridinyl group, a pyrimidinyl group, a pyrazinyl group, a pyridazinyl group, a triazinyl group, a quinolinyl group, and an isoquinolinyl group. When the C₁-C₆₀ heteroaryl group and the C₁-C₆₀ heteroarylene group each include two or more rings, the rings may be fused to each other.

The term “C₆-C₆₀ aryloxy group” used herein indicates —OA₁₀₂ (wherein A₁₀₂ is the C₆-C₆₀ aryl group), and a C₆-C₆₀ arylthio group used herein indicates —SA₁₀₃ (wherein A₁₀₃ is the C₆-C₆₀ aryl group).

The term “monovalent non-aromatic condensed polycyclic group” as used herein refers to a monovalent group (for example, having 8 to 60 carbon atoms) having two or more rings condensed to each other, having only carbon atoms as ring-forming atoms, and that is not aromatic in its entire molecular structure. Examples of the monovalent non-aromatic condensed polycyclic group include a fluorenyl group. The term “divalent non-aromatic condensed polycyclic group” as used herein refers to a divalent group having the same structure as the monovalent non-aromatic condensed polycyclic group.

The term “monovalent non-aromatic condensed heteropolycyclic group” as used herein refers to a monovalent group (for example, having 2 to 60 carbon atoms) having two or more rings condensed to each other, having a heteroatom selected from N, O, P, Si, and S, other than carbon atoms, as a ring-forming atom, and that is not aromatic in its entire molecular structure. Non-limiting examples of the monovalent non-aromatic condensed heteropolycyclic group include a carbazolyl group. The term “divalent non-aromatic condensed heteropolycyclic group” as used herein refers to a divalent group having the same structure as the monovalent non-aromatic condensed heteropolycyclic group.

The term “C₅-C₃₀ carbocyclic group” as used herein refers to a saturated or unsaturated cyclic group having, as a ring-forming atom, 5 to 30 carbon atoms only. The C₅-C₃₀ carbocyclic group may be a monocyclic group or a polycyclic group.

The term “C₁-C₃₀ heterocyclic group” as used herein refers to a saturated or unsaturated cyclic group having, as a ring-forming atom, at least one heteroatom selected from N, O, Si, P, and S other than 1 to 30 carbon atoms. The C₁-C₃₀ heterocyclic group may be a monocyclic group or a polycyclic group.

At least one of substituents of the substituted C₅-C₃₀ carbocyclic group, substituted C₂-C₃₀ heterocyclic group, substituted C₁-C₆₀ alkyl group, substituted C₂-C₆₀ alkenyl group, substituted C₂-C₆₀ alkynyl group, substituted C₁-C₆₀ alkoxy group, substituted C₃-C₁₀ cycloalkyl group, substituted C₁-C₁₀ heterocycloalkyl group, substituted C₃-C₁₀ cycloalkenyl group, substituted C₁-C₁₀ heterocycloalkenyl group, substituted C₆-C₆₀ aryl group, substituted C₆-C₆₀ aryloxy group, substituted C₆-C₆₀ arylthio group, substituted C₁-C₆₀ heteroaryl group, substituted monovalent non-aromatic condensed polycyclic group, and substituted monovalent non-aromatic condensed heteropolycyclic group may be selected from:

deuterium, —F, —Cl, —Br, —I, —CD₃, —CD₂H, —CDH₂, —CF₃, —CF₂H, —CFH₂, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, and a C₁-C₆₀ alkoxy group;

a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, and a C₁-C₆₀ alkoxy group, each substituted with at least one selected from deuterium, —F, —Cl, —Br, —I, —CD₃, —CD₂H, —CDH₂, —CF₃, —CF₂H, —CFH₂, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, a monovalent non-aromatic condensed polycyclic group, a monovalent non-aromatic condensed heteropolycyclic group, —N(Q₁₁)(Q₁₂), —Si(Q₁₃)(Q₁₄)(Q₁₅), —B(Q₁₆)(Q₁₇), and —P(═O)(Q₁₈)(Q₁₉);

a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, a monovalent non-aromatic condensed polycyclic group, and a monovalent non-aromatic condensed heteropolycyclic group;

a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, a monovalent non-aromatic condensed polycyclic group, and a monovalent non-aromatic condensed heteropolycyclic group, each substituted with at least one selected from deuterium, —F, —Cl, —Br, —I, —CD₃, —CD₂H, —CDH₂, —CF₃, —CF₂H, —CFH₂, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, a C₁-C₆₀ alkoxy group, a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, a monovalent non-aromatic condensed polycyclic group, a monovalent non-aromatic condensed heteropolycyclic group, —N(Q₂₁)(Q₂₂), —Si(Q₂₃)(Q₂₄)(Q₂₅), —B(Q₂₆)(Q₂₇), and —P(═O)(Q₂₈)(Q₂₉); and

—N(Q₃₁)(Q₃₂), —Si(Q₃₃)(Q₃₄)(Q₃₅), —B(Q₃₆)(Q₃₇), and —P(═O)(Q₃₈)(Q₃₉),

wherein Q₁ to Q₉, Q₁₁ to Q₁₉, Q₂₁ to Q₂₉, and Q₃₁ to Q₃₉ may each independently be selected from hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C₁-C₆₀ alkyl group, a C₁-C₆₀ alkyl group substituted with at least one selected from deuterium, a C₁-C₆₀ alkyl group, and a C₆-C₆₀ aryl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, a C₁-C₆₀ alkoxy group, a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryl group substituted with at least one selected from deuterium, a C₁-C₆₀ alkyl group, and a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, a monovalent non-aromatic condensed polycyclic group, and a monovalent non-aromatic condensed heteropolycyclic group.

When a group containing a specified number of carbon atoms is substituted with any of the groups listed in the preceding paragraph, the number of carbon atoms in the resulting “substituted” group is defined as the sum of the carbon atoms contained in the original (unsubstituted) group and the carbon atoms (if any) contained in the substituent. For example, when the term “substituted C1-C30 alkyl” refers to a C1-C30 alkyl group substituted with C6-C30 aryl group, the total number of carbon atoms in the resulting aryl substituted alkyl group is C7-C60.

Hereinafter, a compound and an organic light-emitting device according to embodiments are described in detail with reference to Synthesis Example and Examples. However, the organic light-emitting device is not limited thereto. The wording “B was used instead of A” used in describing Synthesis Examples refers to that an identical molar equivalent of B was used in place of A.

EXAMPLE Synthesis Example 1: Synthesis of Compound 123

Synthesis of Intermediate P2

120 milliliters (mL) of tetrahydrofuran (THF) and 40 mL of distilled water were mixed with Compound P3-1 (5.3 grams (g), 20.5 millimoles, mmol), Compound P3-2 (7 g, 19.5 mmol), Pd(PPh₃)₄(1.6 g, 1.4 mmol), and K₂CO₃ (8.1 g, 58.6 mmol), and the mixture was stirred under reflux for 12 hours. Once the reaction was completed, the temperature was lowered to room temperature, and the organic layer was extracted therefrom with methylene chloride (MC). The combined organic extracts were dried over anhydrous magnesium sulfate (MgSO₄) and filtered. The obtained filtrate was concentrated under reduced pressure, and the residue was purified by column chromatography using MC and hexane, thereby completing the preparation of 5.8 g (73%) of Intermediate P2.

Synthesis of Intermediate P1

Intermediate P2 (5.8 g, 14.18 mmol), 4,4,4′,4′,5,5,5′,5′-octamethyl-2,2′-bi(1,3,2-dioxaborolane) (7.2 g, 28.36 mmol), PdCl₂(dppf) (0.83 g, 1.1 mmol), and potassium acetate (4.2 g, 42.5 mmol) were mixed with 300 mL of toluene, and the mixture was stirred under reflux for 18 hours. The temperature was lowered down to room temperature. The organic layer was extracted therefrom with MC, and the combined organic extracts were dried over anhydrous magnesium sulfate (MgSO₄) and filtered. The obtained filtrate was subjected to reduced pressure and the residue was purified by column chromatography using EA and hexane, thereby completing the preparation of 5.4 g (83%) of Intermediate P1.

Synthesis of Ligand 123L

Compound A (1.4 g, 2.9 mmol), Intermediate P1 (1.3 g, 2.9 mmol), Pd(PPh₃)₄ (0.24 g, 0.2 mmol), and K₂CO₃ (1.2 g, 8.7 mmol) were mixed with 60 mL of THF and 20 mL of distilled water, and the mixture was stirred under reflux for 12 hours. After the temperature was lowered down to room temperature, the organic layer was extracted therefrom with MC. The combined organic extracts were dried over anhydrous magnesium sulfate (MgSO₄) and filtered. The obtained filtrate was concentrated under reduced pressure and the residue was purified by column chromatography using MC and hexane, thereby completing the preparation of 1.2 g (56%) of Ligand 123L.

Synthesis of Compound 123

Ligand 123L (1.2 g, 1.6 mmol) and K₂PtCl₄ (0.7 g, 1.8 mmol) were mixed with 50 mL of acetic acid, and the mixture was stirred under reflux for 18 hours to complete the reaction. Then, the temperature was lowered. The obtained solid was filtered, and the residue was purified by column chromatography using MC and hexane, thereby obtaining 0.56 g (37%) of Compound 123. The obtained product was confirmed by Mass and HPLC analysis.

HRMS (MALDI) calcd for C₅₁H₄₂N₄OPt: m/z 921.3006, Found: 921.3001

Synthesis Example 2: Compound 128

Synthesis of Ligand 128L

Compound A (2.1 g, 4.3 mmol), Compound B (2.0 g, 4.3 mmol), Pd(PPh₃)₄(0.35 g, 0.3 mmol), and K₂CO₃ (1.8 g, 13.0 mmol) were mixed with 60 mL of THF and 20 mL of distilled water, and the mixture was stirred under reflux for 12 hours. After the temperature was lowered to room temperature, the organic layer was extracted therefrom with MC. The combined organic extracts were dried over anhydrous magnesium sulfate (MgSO₄) and filtered. The obtained filtrate was subjected to reduced pressure and the residue was purified by column chromatography using MC and hexane, thereby completing the preparation of 1.5 g (48%) of Ligand 128L.

Synthesis of Compound 128

Ligand 128L (1.5 g, 2.1 mmol) and K₂PtCl₄ (1.1 g, 2.3 mmol) were mixed with 60 mL of acetic acid, and the mixture was stirred under reflux for 18 hours to complete a reaction. Then, the temperature was lowered. The obtained solid was filtered, and the residue was purified by column chromatography using MC and hexane, thereby obtaining 1.0 g (53%) of Compound 128. The obtained product was confirmed by Mass and HPLC analysis.

HRMS (MALDI) calcd for C₅₁H₄₂N₄OPt: m/z 921.3006, Found: 921.2997 Example 1

A glass substrate with an ITO electrode thereon was cut to a size of 50 mm×50 mm×0.5 mm (mm=millimeter), sonicated in acetone, iso-propyl alcohol and pure water, each for 15 minutes, and washed by exposure to UV ozone for 30 minutes, thereby preparing an ITO electrode on the glass substrate.

Then, m-MTDATA was deposited on the ITO electrode on the glass substrate at a deposition rate of 1 Angstrom per second (A/sec) to form a hole injection layer having a thickness of 600 Angstroms (Å), and α-NPD (NPB) was deposited on the hole injection layer at a deposition rate of 1 Å/sec to form a hole transport layer having a thickness of 250 Å.

Compound 123 (dopant) and CBP (host) were co-deposited on the hole transport layer at deposition rates of 0.1 Å/sec and 1 Å/sec, respectively, to form an emission layer having a thickness of 400 Å.

BAIq was deposited on the emission layer at a deposition rate of 1 Å/sec to form a hole blocking layer having a thickness of 50 Å, Alq₃ was deposited on the hole blocking layer to form an electron transport layer having a thickness of 300 Å, LiF was deposited on the electron transport layer to form an electron injection layer having a thickness of 10 Å, and Al was vacuum-deposited on the electron injection layer to form a second electrode (cathode) having a thickness of 1,200 Å, thereby completing the manufacture of an organic light-emitting device having the structure of ITO/m-MTDATA (600 Å)/α-NPD (250 Å)/CBP+Compound 123 (10%) (400 Å)/Balq(50 Å)/Alq₃(300 Å)/LiF(10 Å)/AI(1,200 Å).

Example 2 and Comparative Example 1

Organic light-emitting devices were manufactured in the same manner as in Example 1, except that in forming an emission layer, for use as a dopant, corresponding compounds shown in Table 2 were used instead of Compound 123.

Evaluation Example 1: Evaluation on Characteristics of Organic Light-Emitting Devices

The driving voltage, the luminescent quantum efficiency, the roll-off ratio, and the lifespan (T₉₅) of each of the organic light-emitting devices manufactured according to Examples 1 and 2 and Comparative Example 1 were evaluated and the results are shown in Table 2. As evaluation devices, a current-voltage meter (Keithley 2400) and a luminance meter (Minolta Cs-1000A) were used, and the lifetime (T₉₅) (at 6000 nit) was a relative value of the time taken when the luminance becomes 95% of the initial luminance 100% with respect to the lifespan (T₉₅) of Example 1. The roll-off ratio was calculated by the following equation: Roll off={1−(efficiency(at 9000 nit)/maximum luminescent efficiency)}×100%  Equation 20

TABLE 2 Driving Luminescent Lifespan voltage quantum Roll-off (relative Voltage Efficiency ratio value) Dopant (V) (%) (%) (T₉₅) Example 1 Compound 4.26 22.6 10% 100% 123 Example 2 Compound 4.21 25.2 13% 112% 128 Comparative Compound 4.57 18.7 11% 17% Example 1 A

From Table 2, it can be seen that the organic light-emitting devices of Examples 1 and 2 have better characteristics than the organic light-emitting device of Comparative Example 1 in terms of driving voltage, luminescent quantum efficiency, roll-off ratio, and lifespan.

The organometallic compound according to embodiments has excellent electric characteristics and thermal stability. Accordingly, an organic light-emitting device including the organometallic compound may have excellent characteristics in terms of driving voltage, efficiency, power, color purity, and lifespan. The organometallic compound has excellent phosphorescent luminescent characteristics. Accordingly, the organometallic compound can provide a diagnostic composition having high diagnostic efficiency.

It should be understood that embodiments described herein should be considered in a descriptive sense only and not for purposes of limitation. Descriptions of features or aspects within each embodiment should typically be considered as available for other similar features or aspects in other embodiments.

While one or more embodiments have been described with reference to the figures, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope as defined by the following claims. 

What is claimed is:
 1. An organometallic compound represented by Formula 1:

wherein, in Formula 1, M is beryllium (Be), magnesium (Mg), aluminum (Al), calcium (Ca), titanium (Ti), manganese (Mn), cobalt (Co), copper (Cu), zinc (Zn), gallium (Ga), germanium (Ge), zirconium (Zr), rhutenium (Ru), rhodium (Rh), palladium (Pd), silver (Ag), rhenium (Re), platinum (Pt), or gold (Au), X₁ is a chemical bond, and Y₁ is directly bonded with M, a bond between X₁ and M is a covalent bond, X₂ to X₄ are each independently N or C, one bond selected from a bond between X₂ and M, a bond between X₃ and M, and a bond between X₄ and M is a covalent bond, and the remaining two bonds are coordinate bonds, Y₁ and Y₃ to Y₅ are each independently C or N, regarding a pair of X₂ and Y₃, a pair of X₂ and Y₄, a pair of Y₄ and Y₅, a pair of X₅₁ and Y₃, and a pair of X₅₁ and Y₅, components constituting each pair are connected to each other via a chemical bond, CY₁ to CY₅ are each independently selected from a C₅-C₃₀ carbocyclic group and a C₁-C₃₀ heterocyclic group, a moiety represented by

is a group represented by CY1-B,

wherein Formula CY1-B, Y₂ and Y₆ are each independently N or C, and a bond between Y₁ and Y₂, an bond between Y₁ and Y₆, and a bond between Y₆ and Y₂ are each a chemical bond, a cyclometalated ring formed by CY₅, CY₂, CY₃, and M is a 6-membered ring, X₅₁ is selected from O, S, N-[(L₇)_(b7)-(R₇)_(c7)], C(R₇)(R₈), Si(R₇)(R₈), Ge(R₇)(R₈), C(═C(═O), N, C(R₇), Si(R₇), and Ge(R₇), R₇ and R₈ are optionally bonded to each other via a first linking group to form a substituted or unsubstituted C₅-C₃₀ carbocyclic group or a substituted or unsubstituted C₁-C₃₀ heterocyclic group, L₁ to L₄ and L₇ are each independently selected from a single bond, a substituted or unsubstituted C₅-C₃₀ carbocyclic group, and a substituted or unsubstituted C₁-C₃₀ heterocyclic group, b1 to b4 and b7 are each independently an integer from 1 to 5, R₁ to R₄, R₇, R₈, R′, and R″ are each independently selected from hydrogen, deuterium, —F, —Cl, —Br, —I, —SF₅, a hydroxyl group, a cyano group, a nitro group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a substituted or unsubstituted C₁-C₆₀ alkyl group, a substituted or unsubstituted C₂-C₆₀ alkenyl group, a substituted or unsubstituted C₂-C₆₀ alkynyl group, a substituted or unsubstituted C₁-C₆₀ alkoxy group, a substituted or unsubstituted C₃-C₁₀ cycloalkyl group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkyl group, a substituted or unsubstituted C₃-C₁₀ cycloalkenyl group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkenyl group, a substituted or unsubstituted C₆-C₆₀ aryl group, a substituted or unsubstituted C₆-C₆₀ aryloxy group, a substituted or unsubstituted C₆-C₆₀ arylthio group, a substituted or unsubstituted C₁-C₆₀ heteroaryl group, a substituted or unsubstituted monovalent non-aromatic condensed polycyclic group, a substituted or unsubstituted monovalent non-aromatic condensed heteropolycyclic group, —N(Q₁)(Q₂), —Si(Q₃)(Q₄)(Q₅), —B(Q₆)(Q₇), and —P(═O)(Q₈)(Q₉), c1 to c4 and c7 are each independently an integer from 1 to 5, Z₁ to Z₄ are each independently a cyano group (CN)-containing group, a1 to a4 and n1, n2, n3, and n4 are each independently an integer from 0 to 20, two of a plurality of neighboring groups R₁ are optionally linked to form a substituted or unsubstituted C₅-C₃₀ carbocyclic group or a substituted or unsubstituted C₁-C₃₀ heterocyclic group, two of a plurality of neighboring groups R₂ are optionally linked to form a substituted or unsubstituted C₅-C₃₀ carbocyclic group or a substituted or unsubstituted C₁-C₃₀ heterocyclic group, two of a plurality of neighboring groups R₃ are optionally linked to form a substituted or unsubstituted C₅-C₃₀ carbocyclic group or a substituted or unsubstituted C₁-C₃₀ heterocyclic group, two of a plurality of neighboring groups R₄ are optionally linked to form a substituted or unsubstituted C₅-C₃₀ carbocyclic group or a substituted or unsubstituted C₁-C₃₀ heterocyclic group, two or more neighboring substituents selected from groups R₁ to R₄, R₇, and R₈ are optionally linked to form a substituted or unsubstituted C₅-C₃₀ carbocyclic group or a substituted or unsubstituted C₁-C₃₀ heterocyclic group, i) when X₅₁ is O, S, C(═O), or N, the sum of n1, n2, n3, and n4 is 1 or more, ii) when X₅₁ is N[(L₇)_(b7)-(R₇)_(c7)], C(R₇), Si(R₇), or Ge(R₇), R₇ is a cyano group-containing group or the sum of n1, n3, and n4 is 1 or more, iii) when X₅₁ is C(R₇)(R₈), Si(R₇)(R₈), or Ge(R₇)(R₈), at least one selected from R₇ and R₈ is a cyano group-containing group or the sum of n1, n3, and n4 is 1 or more,

wherein in Formula 1, at least one substituent of the substituted C₅-C₃₀ carbocyclic group, substituted C₁-C₃₀ heterocyclic group, substituted C₁-C₆₀ alkyl group, substituted C₂-C₆₀ alkenyl group, substituted C₂-C₆₀ alkynyl group, substituted C₁-C₆₀ alkoxy group, substituted C₃-C₁₀ cycloalkyl group, substituted C₁-C₁₀ heterocycloalkyl group, substituted C₃-C₁₀ cycloalkenyl group, substituted C₁-C₁₀ heterocycloalkenyl group, substituted C₆-C₆₀ aryl group, substituted C₆-C₆₀ aryloxy group, substituted C₆-C₆₀ arylthio group, substituted C₁-C₆₀ heteroaryl group, substituted monovalent non-aromatic condensed polycyclic group, and substituted monovalent non-aromatic condensed heteropolycyclic group is selected from: deuterium, —F, —Cl, —Br, —I, —CD₃, —CD₂H, —CDH₂, —CF₃, —CF₂H, —CFH₂, a hydroxyl group, a cyano group, a nitro group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, and a C₁-C₆₀ alkoxy group; a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, and a C₁-C₆₀ alkoxy group, each substituted with at least one selected from deuterium, —F, —Cl, —Br, —I, —CD₃, —CD₂H, —CDH₂, —CF₃, —CF₂H, —CFH₂, a hydroxyl group, a cyano group, a nitro group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, a monovalent non-aromatic condensed polycyclic group, a monovalent non-aromatic condensed heteropolycyclic group, —N(Q₁₁)(Q₁₂), —Si(Q₁₃)(Q₁₄)(Q₁₅), —B(Q₁₆)(Q₁₇), and —P(═O)(Q₁₈)(Q₁₉); a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, a monovalent non-aromatic condensed polycyclic group, and a monovalent non-aromatic condensed heteropolycyclic group; a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, a monovalent non-aromatic condensed polycyclic group, and a monovalent non-aromatic condensed heteropolycyclic group, each substituted with at least one selected from deuterium, —F, —Cl, —Br, —I, —CD₃, —CD₂H, —CDH₂, —CF₃, —CF₂H, —CFH₂, a hydroxyl group, a cyano group, a nitro group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, a C₁-C₆₀ alkoxy group, a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, a monovalent non-aromatic condensed polycyclic group, a monovalent non-aromatic condensed heteropolycyclic group, —N(Q₂₁)(Q₂₂), —Si(Q₂₃)(Q₂₄)(Q₂₅), —B(Q₂₆)(Q₂₇), and —P(═O)(Q₂₈)(Q₂₉), and —N(Q₃₁)(Q₃₂), —Si(Q₃₃)(Q₃₄)(Q₃₅), —B(Q₃₆)(Q₃₇), and —P(═O)(Q₃₈)(Q₃₉), wherein Q₁ to Q₉, Q₁₁ to Q₁₉, Q₂₁ to Q₂₉, and Q₃₁ to Q₃₉ are each independently selected from hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C₁-C₆₀ alkyl group, a C₁-C₆₀ alkyl group substituted with at least one selected from deuterium, a C₁-C₆₀ alkyl group, and a C₆-C₆₀ aryl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, a C₁-C₆₀ alkoxy group, a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryl group substituted with at least one selected from deuterium, a C₁-C₆₀ alkyl group, and a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, a monovalent non-aromatic condensed polycyclic group, and a monovalent non-aromatic condensed heteropolycyclic group.
 2. The organometallic compound of claim 1, wherein i) X₂ and X₄ are each N, X₃ is C, a bond between X₂ and M and a bond between X₄ and M are each a coordinate bond, and a bond between X₃ and M is a covalent bond, ii) X₃ and X₄ are each N, X₂ is N, a bond between X₃ and M and a bond between X₄ and M are each a coordinate bond, and a bond between X₂ and M is a covalent bond, iii) X₂ and X₃ are each N, X₄ is N, a bond between X₂ and M is a covalent bond, and a bond between X₃ and M and a bond between X₄ and M are each a coordinate bond, or iv) X₂ and X₃ are each N, X₄ is C, a bond between X₂ and M and a bond between X₃ and M are each a coordinate bond, and a bond between X₄ and M is a covalent bond.
 3. The organometallic compound of claim 1, wherein CY₁ to CY₄ are each independently selected from a benzene group, a naphthalene group, an anthracene group, a phenanthrene group, a triphenylene group, a pyrene group, a chrysene group, a cyclopentadiene group, a 1,2,3,4-tetrahydronaphthalene group, a furan group, a thiophene group, a silole group, an indene group, a fluorene group, an indole group, a carbazole group, a benzofuran group, a dibenzofuran group, a benzothiophene group, a dibenzothiophene group, a benzosilole group, a dibenzosilole group, an azafluorene group, an azacarbazole group, an azadibenzofuran group, an azadibenzothiophene group, an azadibenzosilole group, a pyridine group, a pyrimidine group, a pyrazine group, a pyridazine group, a triazine group, a quinoline group, an isoquinoline group, a quinoxaline group, a quinazoline group, phenanthroline group, a pyrrole group, a pyrazole group, an imidazole group, a triazole group, an oxazole group, an iso-oxazole group, a thiazole group, an isothiazole group, an oxadiazole group, a thiadiazole group, a benzopyrazole group, a benzimidazole group, a benzoxazole group, a benzothiazole group, a benzooxadiazole group, a benzothiadiazole group, a 5,6,7,8-tetrahydroisoquinoline group, and a 5,6,7,8-tetrahydroquinoline.
 4. The organometallic compound of claim 1, wherein i) Y₃ to Y₅ are each C, a bond between X₅₁ and Y₃ and a bond between X₅₁ and Y₅ are each a single bond, and X₅₁ is O, S, N-[(L₇)_(b7)-(R₇)_(c7)], C(R₇)(R₈), Si(R₇)(R₈), Ge(R₇)(R₈), or C(═O), ii) Y₃ and Y₄ are each C, Y₅ is N, a bond between X₅₁ and Y₃ is a double bond, a bond between X₅₁ and Y₅ is a single bond, and X₅₁ is N, C(R₇), Si(R₇), or Ge(R₇), iii) Y₃ and Y₅ are each C, Y₄ is N, a bond between X₅₁ and Y₃ is a single bond, a bond between X₅₁ and Y₅ is a double bond, and X₅₁ is N, C(R₇), Si(R₇), or Ge(R₇), iv) Y₃ is N, Y₄ and Y₅ are each C, a bond between X₅₁ and Y₃ is a single bond, a bond between X₅₁ and Y₅ is a double bond, and X₅₁ is N, C(R₇), Si(R₇), or Ge(R₇), or v) Y₃ to Y₅ are each C, a bond between X₅₁ and Y₃ is a double bond, a bond between X₅₁ and Y₅ is a single bond, and X₅₁ is N, C(R₇), Si(R₇), or Ge(R₇).
 5. The organometallic compound of claim 1, wherein R₁ to R₄, R₇, R₈, R′, and R″ are each independently selected from: hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, —SF₅, C₁-C₂₀ alkyl group, and a C₁-C₂₀ alkoxy group; a C₁-C₂₀ alkyl group and a C₁-C₂₀ alkoxy group, each substituted with at least one selected from deuterium, —F, —Cl, —Br, —I, —CD₃, —CD₂H, —CDH₂, —CF₃, —CF₂H, —CFH₂, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C₁-C₁₀ alkyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, an adamantanyl group, a norbornanyl group, a norbornenyl group, a cyclopentenyl group, a cyclohexenyl group, a cycloheptenyl group, a phenyl group, a naphthyl group, a pyridinyl group, and a pyrimidinyl group; a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, an adamantanyl group, a norbornanyl group, a norbornenyl group, a cyclopentenyl group, a cyclohexenyl group, a cycloheptenyl group, a phenyl group, a naphthyl group, a fluorenyl group, a phenanthrenyl group, an anthracenyl group, a fluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenyl group, a pyrrolyl group, a thiophenyl group, a furanyl group, an imidazolyl group, a pyrazolyl group, a thiazolyl group, an isothiazolyl group, an oxazolyl group, an isoxazolyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, an isoindolyl group, an indolyl group, an indazolyl group, a purinyl group, a quinolinyl group, an isoquinolinyl group, a benzoquinolinyl group, a quinoxalinyl group, a quinazolinyl group, a cinnolinyl group, a carbazolyl group, a phenanthrolinyl group, a benzimidazolyl group, a benzofuranyl group, a benzothiophenyl group, an isobenzothiazolyl group, a benzoxazolyl group, an isobenzoxazolyl group, a triazolyl group, a tetrazolyl group, an oxadiazolyl group, a triazinyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a dibenzosilolyl group, a benzocarbazolyl group, a dibenzocarbazolyl group, an imidazopyridinyl group, and an imidazopyrimidinyl group; a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, an adamantanyl group, a norbornanyl group, a norbornenyl group, a cyclopentenyl group, a cyclohexenyl group, a cycloheptenyl group, a phenyl group, a naphthyl group, a fluorenyl group, a phenanthrenyl group, an anthracenyl group, a fluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenyl group, a pyrrolyl group, a thiophenyl group, a furanyl group, an imidazolyl group, a pyrazolyl group, a thiazolyl group, an isothiazolyl group, an oxazolyl group, an isoxazolyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, an isoindolyl group, an indolyl group, an indazolyl group, a purinyl group, a quinolinyl group, an isoquinolinyl group, a benzoquinolinyl group, a quinoxalinyl group, a quinazolinyl group, a cinnolinyl group, a carbazolyl group, a phenanthrolinyl group, a benzimidazolyl group, a benzofuranyl group, a benzothiophenyl group, an isobenzothiazolyl group, a benzoxazolyl group, an isobenzoxazolyl group, a triazolyl group, a tetrazolyl group, an oxadiazolyl group, a triazinyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a dibenzosilolyl group, a benzocarbazolyl group, a dibenzocarbazolyl group, an imidazopyridinyl group, and an imidazopyrimidinyl group, each substituted with at least one selected from; and deuterium, —F, —Cl, —Br, —I, —CD₃, —CD₂H, —CDH₂, —CF₃, —CF₂H, —CFH₂, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, an adamantanyl group, a norbornanyl group, a norbornenyl group, a cyclopentenyl group, a cyclohexenyl group, a cycloheptenyl group, a phenyl group, a naphthyl group, a fluorenyl group, a phenanthrenyl group, an anthracenyl group, a fluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenyl group, a pyrrolyl group, a thiophenyl group, a furanyl group, an imidazolyl group, a pyrazolyl group, a thiazolyl group, an isothiazolyl group, an oxazolyl group, an isoxazolyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, an isoindolyl group, an indolyl group, an indazolyl group, a purinyl group, a quinolinyl group, an isoquinolinyl group, a benzoquinolinyl group, a quinoxalinyl group, a quinazolinyl group, a cinnolinyl group, a carbazolyl group, a phenanthrolinyl group, a benzimidazolyl group, a benzofuranyl group, a benzothiophenyl group, an isobenzothiazolyl group, a benzoxazolyl group, an isobenzoxazolyl group, a triazolyl group, a tetrazolyl group, an oxadiazolyl group, a triazinyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a dibenzosilolyl group, a benzocarbazolyl group, a dibenzocarbazolyl group, an imidazopyridinyl group, an imidazopyrimidinyl group, and —Si(Q₃₃)(Q₃₄)(Q₃₅), and —N(Q₁)(Q₂), —Si(Q₃)(Q₄)(Q₅), —B(Q₆)(Q₇) and —P(═O)(Q₈)(Q₉), wherein Q₁ to Q₉ and Q₃₃ to Q₃₅ are each independently selected from: —CH₃, —CD₃, —CD₂H, —CDH₂, —CH₂CH₃, —CH₂CD₃, —CH₂CD₂H, —CH₂CDH₂, —CHDCH₃, —CHDCD₂H, —CHDCDH₂, —CHDCD₃, —CD₂CD₃, —CD₂CD₂H, and —CD₂CDH₂; an n-propyl group, an iso-propyl group, an n-butyl group, an iso-butyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, an iso-pentyl group, a sec-pentyl group, a tert-pentyl group, a phenyl group, and a naphthyl group; and an n-propyl group, an iso-propyl group, an n-butyl group, an iso-butyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, an iso-pentyl group, a sec-pentyl group, a tert-pentyl group, a phenyl group, and a naphthyl group, each substituted with at least one selected from deuterium, a C₁-C₁₀ alkyl group, and a phenyl group.
 6. The organometallic compound of claim 1, wherein R₁ to R₄, R₇, R₈, R′, and R″ are each independently selected from hydrogen, deuterium, —F, a cyano group, a nitro group, —SF₅, —CH₃, —CD₃, —CD₂H, —CDH₂, —CF₃, —CF₂H, —CFH₂, —C(CD₃)₃, groups represented by Formulae 9-1 to 9-19, groups represented by Formulae 10-1 to 10-140, —N(Q₁)(Q₂), —Si(Q₃)(Q₄)(Q₅), —B(Q₆)(Q₇), and —P(═O)(Q₈)(Q₉):

wherein, in Formulae 9-1 to 9-19 and 10-1 to 10-140, * indicates a binding site to a neighboring atom, “Ph” indicates a phenyl group, and “TMS” indicates a trimethylsilyl group.
 7. The organometallic compound of claim 1, wherein the cyano group-containing group is a cyano group or a first group substituted with at least one cyano group, wherein the first group is selected from a substituted or unsubstituted C₁-C₆₀ alkyl group, a substituted or unsubstituted C₂-C₆₀ alkenyl group, a substituted or unsubstituted C₂-C₆₀ alkynyl group, a substituted or unsubstituted C₁-C₆₀ alkoxy group, a substituted or unsubstituted C₃-C₁₀ cycloalkyl group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkyl group, a substituted or unsubstituted C₃-C₁₀ cycloalkenyl group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkenyl group, a substituted or unsubstituted C₆-C₆₀ aryl group, a substituted or unsubstituted C₆-C₆₀ aryloxy group, a substituted or unsubstituted C₆-C₆₀ arylthio group, a substituted or unsubstituted C₁-C₆₀ heteroaryl group, a substituted or unsubstituted monovalent non-aromatic condensed polycyclic group, and a substituted or unsubstituted monovalent non-aromatic condensed heteropolycyclic group.
 8. The organometallic compound of claim 1, wherein the sum of n1, n2, n3, and n4 is 1, 2, 3, or
 4. 9. The organometallic compound of claim 1, wherein i) n1=n2=n3=0, and n4=1, ii) n1=n2=n4=0, and n3=1, iv) n2=n3=n4=0, and n1=1, v) n1=n2=0, and n3=n4=1, vi) n2=n3=0, and n1=n4=1, vii) n2=n4=0, and n1=n3=1, or viii) n1=n3=0, and n2=n4=1.
 10. The organometallic compound of claim 1, wherein a moiety represented by

in Formula 1 is a group represented by one of the Formula CY1-27 to CY1-40

Wherein, in Formulae CY1-27 to CY1-40, Y₁, R₁ and n 1 are the same as described in connection with claim 1, n1 is 0, 1, or 2, X₁₉ is C(R_(19a))(R_(19b)), N[(L₁₉)_(b19)-(R₁₉)_(c19,) O, S, or Si(R_(19a))(R_(19b)), L₁₉ is the same as described in connection with L₁ in claims 1 b19 and c19 are the same as described in connection with b1 and c1 in claim 1, respectively R₁₁ to R₁₉, R_(19a) and R_(19b) are the same as described in connection with R₁ in claim 1, a14 is an integer from 0 to 4 a15 is an integer from 0 to 5 a16 is an integer from 0 to 6 a17 is an integer from 0 to 7 *′ indicates a binding site to M in Formula 1, and *indicates a binding site to CY₅ in Formula
 1. 11. The organometallic compound of claim 1, wherein a moiety represented by

in Formula 1 is a group represented by one of Formulae CY2-1 to CY2-20:

wherein, in Formulae CY2-1 to CY2-20, R₂, Z₂, and n2 are the same as described in connection with claim 1, n2 is 0, 1, or 2, X₅₁ in Formulae CY2-1 to CY2-4 is O, S, N-[(L₇)_(b7)-(R₇)_(c7)], C(R₇)(R₈), Si(R₇)(R₈), Ge(R₇)(R₈), or C(═O), X₅₁ in Formulae CY2-5 to CY2-20 is N, C(R₇), Si(R₇), or Ge(R₇), L₇, b7, R₇, and c7 are the same as described in connection with claim 1, a22 is an integer from 0 to 2, a23 is an integer from 0 to 3, * indicates a binding site to CY₁ in Formula 1, *′ indicates a binding site to M in Formula 1, and *″ indicates a binding site to CY₃ in Formula
 1. 12. The organometallic compound of claim 1, wherein a moiety represented by

in Formula 1 is a group represented by one of Formulae CY3-1 to CY3-12:

wherein, in Formulae CY3-1 to CY3-12, X₃, R₃, Z₃, and n3 are the same as described in connection with claim 1, n3 is 0, 1 or 2, X₃₉ is C(R_(39a))(R_(39b)), N[(L₃₉)b₃₉-(R₃₉)_(c39)], O, S, or Si(R_(39a))(R_(39b)), L₃₉ is the same as described in connection with L₃ in claim 1, b39 and c39 are the same as described in connection with b3 and c3 recited in claim 1, respectively, R_(39a) and R_(39b) are the same as described in connection with R₃ in claim 1, a32 is an integer from 0 to 2, a33 is an integer from 0 to 3, a34 is an integer from 0 to 4, a35 is an integer from 0 to 5, *indicates a binding site to CY₄ in Formula 1, *′ indicates a binding site to M in Formula 1, and *″ indicates a binding site to CY₂ in Formula
 1. 13. The organometallic compound of claim 1, wherein a moiety represented by

in Formula 1 is a group represented by one of Formulae CY4-1 to CY4-26:

wherein, in Formulae CY4-1 to CY4-26, X₄, R₄, Z₄, and n4 are the same as described in connection with claim 1, n4 is 0, 1, or 2, X₄₉ is C(R_(49a))(R_(49b)), N[(L₄₉)_(b49)-(R₄₉)_(c49)], O, S, or Si(R_(49a))(R_(49b)), L₄₉ is the same as described in connection with L₄ in claim 1, b49 and c49 are the same as described in connection with b4 and c4 in claim 1, respectively, R₄₁ to R₄₉, R_(49a) and R_(49b) are the same as described in connection with R₄ in claim 1, a42 is an integer from 0 to 2, a43 is an integer from 0 to 3, a44 is an integer from 0 to 4, a45 is an integer from 0 to 5, a46 is an integer from 0 to 6, *indicates a binding site to CY₃ in Formula 1, and *′ indicates a binding site to M in Formula
 1. 14. An organic light-emitting device comprising: a first electrode; a second electrode; and an organic layer disposed between the first electrode and the second electrode, wherein the organic layer comprising an emission layer, and wherein the organic layer comprises at least one organometallic compound of claim
 1. 15. The organic light-emitting device of claim 14, wherein the first electrode is an anode, the second electrode is a cathode, and the organic layer further comprises a hole transport region disposed between the first electrode and the emission layer and an electron transport region disposed between the emission layer and the second electrode, wherein the hole transport region comprises a hole injection layer, a hole transport layer, an electron blocking layer, or any combination thereof, and wherein the electron transport region comprises a hole blocking layer, an electron transport layer, an electron injection layer, or any combination thereof.
 16. The organic light-emitting device of claim 14, wherein the emission layer comprises the at least one organometallic compound.
 17. The organic light-emitting device of claim 16, wherein the emission layer further comprises a host, and wherein an amount of the host is greater than an amount of the at least one organometallic compound.
 18. A diagnostic composition comprising at least one organometallic compound of claim
 1. 